http://marspedia.org/api.php?action=feedcontributions&user=RichardWSmith&feedformat=atomMarspedia - User contributions [en]2024-03-29T02:23:11ZUser contributionsMediaWiki 1.34.2http://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140906Extreme Energy Cosmic Rays2024-03-12T16:13:35Z<p>RichardWSmith: Added word to make sentence more accurate.</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we may need new physics!) One suggestion that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle | "The Oh My God particle"]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Calcium_carbonate&diff=140905Calcium carbonate2024-03-12T16:11:40Z<p>RichardWSmith: Carbonates are rarer on Mars than expected.</p>
<hr />
<div>Calcium carbonate is one of the main components of Portland cement, and therefore of [[concrete]], the most common building material on Earth. It would be useful as a component for construction materials for Martian infrastructure.<br />
<br />
Calcium carbonate is a [[Elements on Mars|chemical compound]], CaCO3. It has been identified from orbit on Mars as well as through surface exploration (Spirit rover). With the realization that large areas of Mars have been under water for long periods, carbonate deposits are expected, but their extend is yet to be determined.<br />
<br />
Our theories of Mars' history suggest that various carbonate minerals should be common, but they seem to be quite rare on Mars. The reason for this is unknown.</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140896Extreme Energy Cosmic Rays2024-03-04T23:11:33Z<p>RichardWSmith: /* Discussion */ Tried to clear up a formatting error.</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggestion that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle | "The Oh My God particle"]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140895Solar Cosmic Rays2024-03-04T23:05:24Z<p>RichardWSmith: /* Frequency and Energies of Solar Storms */ fixed typo.</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have time to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]] <br />
<br />
[[Extra Galactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Brick&diff=140894Brick2024-03-04T22:52:51Z<p>RichardWSmith: Reversed sentence order to make meaning clearer.</p>
<hr />
<div>Starting from Martian clay or other materials, a brick-maker can create a wide variety of structures and paved surfaces as well as furnaces and ovens for smelting, blacksmithing, glass-blowing, cooking, etc. The brick-making craft requires only other small-scale crafts for its equipment (blacksmithing for its iron tools), thus qualifies as a small-scale craft suitable for a frontier town (small and largely self-sufficient) economy.<br />
<br />
Due to the 1/3 gravity, structures made out of brick can be much larger than on Earth, yet still hold up under their own weight and be easy to transport. However, due to the internal pressure required for most martian buildings, brick construction that also has to withstand pressure requires a separate air tight bladder structure or substantial reinforcements.<br />
<br />
==Material==<br />
The brick can be made from [[regolith]], [[plastics]], [[fiberglass]] or composite materials. Regolith can be [[sintered regolith|sintered]] at high temperatures. A mixture of molten plastics and regolith powder can be produced at moderate temperatures. Bricks can be made stronger by having fibrous material in them. (e.g. ancient bricks were mixed with straw.) This could be plant stalks, plastics, glass fibres, etc.<br />
<br />
==Keep Brick Structures Under Compression==<br />
Bricks stand up well to forces that push them together, but the mortar (if any) is weaker, and brick structures do not stand up well to sideways forces. Building a brick structure on Mars, where the inside is pressurized is problematic, the sideways force created by the air pressure, would break the walls. If you want to have pressurized brick structures, either the air must be contained some other way (e.g. in an inflatable structure) or enough weight must be pressing down to keep the structure stable. Estimates of 6.5 meters of dirt above the structure would be safe. (If the Mars base used 40 bar rather than 100 bar air pressure, this weight could be reduced. Only 2.5 meters would be needed.) See "The Case for Mars" page 191 for more discussion on this point. Note that 6.5 meters of dirt above colony structures would provide excellent [[radiation]] protection. <br />
<br />
==Brick Manufacturing==<br />
"In fact, the UC San Diego engineers were initially trying to cut down on the amount of polymers required to shape Martian soil into bricks, and accidently discovered that none was needed. To make bricks out of Mars soil simulant, without additives and without heating or baking the material, two steps were key. One was to enclose the simulant in a flexible container, in this case a rubber tube. The other was to compact the simulant at a high enough pressure. The amount of pressure needed for a small sample is roughly the equivalent of someone dropping 10-lb hammer from a height of one meter, Qiao said.<br />
<br />
The process produces small round soil pallets that are about an inch tall and can then be cut into brick shapes. The engineers believe that the iron oxide, which gives Martian soil its signature reddish hue, acts as a binding agent. They investigated the simulant's structure with various scanning tools and found that the tiny iron particles coat the simulant's bigger rocky basalt particles. The iron particles have clean, flat facets that easily bind to one another under pressure."<ref>Brian J. Chow, Tzehan Chen, Ying Zhong, Yu Qiao., University of California - San Diego. (2017, April 27). Engineers investigate a simple, no-bake recipe to make bricks from Martian soil. ScienceDaily. Retrieved November 16, 2021 from www.sciencedaily.com/releases/2017/04/170427091723.htm</ref><ref>Brian J. Chow, Tzehan Chen, Ying Zhong, Yu Qiao. Direct Formation of Structural Components Using a Martian Soil Simulant. Sci Rep 7, 1151 (2017). https://doi.org/10.1038/s41598-017-01157-w</ref><br />
<br />
==[[Embodied energy]]==<br />
Different types of brick require different amounts of energy to produce.<br />
{| class="wikitable"<br />
|+<br />
!Materials<br />
!Embodied energy<br />
(MJ/kg)<br />
!Density <br />
(kg/m3)<br />
!Production<br />
|-<br />
|Regolith<br />
|0,5<br />
|2000<br />
|Regolith compressed and combined with some form of cement<br />
|-<br />
|Clay<br />
|3<br />
|2000<br />
|Martian clay baked and fired<br />
|-<br />
|Plastic<br />
|80-100<br />
|900<br />
|Plastic from biomass or CO2+hydrogen reactions<br />
|-<br />
|Glass<br />
|15<br />
|2500<br />
|Silica, cleaned and with required additives<br />
|}<br />
<br />
==See Also==<br />
[[Universal bricks]]<br />
<br />
[[Category:Construction, Assembly, Maintenance]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Brick&diff=140893Brick2024-03-04T22:51:39Z<p>RichardWSmith: Fibers make bricks stronger. Discussion on keeping bricks under pressure.</p>
<hr />
<div>Starting from Martian clay or other materials, a brick-maker can create a wide variety of structures and paved surfaces as well as furnaces and ovens for smelting, blacksmithing, glass-blowing, cooking, etc. The brick-making craft requires only other small-scale crafts for its equipment (blacksmithing for its iron tools), thus qualifies as a small-scale craft suitable for a frontier town (small and largely self-sufficient) economy.<br />
<br />
Due to the 1/3 gravity, structures made out of brick can be much larger than on Earth, yet still hold up under their own weight and be easy to transport. However, due to the internal pressure required for most martian buildings, brick construction that also has to withstand pressure requires a separate air tight bladder structure or substantial reinforcements.<br />
<br />
==Material==<br />
The brick can be made from [[regolith]], [[plastics]], [[fiberglass]] or composite materials. Regolith can be [[sintered regolith|sintered]] at high temperatures. A mixture of molten plastics and regolith powder can be produced at moderate temperatures. Bricks can be made stronger by having fibrous material in them. (e.g. ancient bricks were mixed with straw.) This could be plant stalks, plastics, glass fibres, etc.<br />
<br />
==Keep Brick Structures Under Compression==<br />
Bricks stand up well to forces that push them together, but the mortar (if any) is weaker, and brick structures do not stand up well to sideways forces. Building a brick structure on Mars, where the inside is pressurized is problematic, the sideways force created by the air pressure, would break the walls. If you want to have pressurized brick structures, either the air must be contained some other way (e.g. in an inflatable structure) or enough weight must be pressing down to keep the structure stable. Estimates of 6.5 meters of dirt above the structure would be safe. (If the Mars base used 40 bar rather than 100 bar air pressure, this weight could be reduced. Only 2.5 meters would be needed.) Note that 6.5 meters of dirt above colony structures would provide excellent [[radiation]] protection. See "The Case for Mars" page 191 for more discussion on this point.<br />
<br />
==Brick Manufacturing==<br />
"In fact, the UC San Diego engineers were initially trying to cut down on the amount of polymers required to shape Martian soil into bricks, and accidently discovered that none was needed. To make bricks out of Mars soil simulant, without additives and without heating or baking the material, two steps were key. One was to enclose the simulant in a flexible container, in this case a rubber tube. The other was to compact the simulant at a high enough pressure. The amount of pressure needed for a small sample is roughly the equivalent of someone dropping 10-lb hammer from a height of one meter, Qiao said.<br />
<br />
The process produces small round soil pallets that are about an inch tall and can then be cut into brick shapes. The engineers believe that the iron oxide, which gives Martian soil its signature reddish hue, acts as a binding agent. They investigated the simulant's structure with various scanning tools and found that the tiny iron particles coat the simulant's bigger rocky basalt particles. The iron particles have clean, flat facets that easily bind to one another under pressure."<ref>Brian J. Chow, Tzehan Chen, Ying Zhong, Yu Qiao., University of California - San Diego. (2017, April 27). Engineers investigate a simple, no-bake recipe to make bricks from Martian soil. ScienceDaily. Retrieved November 16, 2021 from www.sciencedaily.com/releases/2017/04/170427091723.htm</ref><ref>Brian J. Chow, Tzehan Chen, Ying Zhong, Yu Qiao. Direct Formation of Structural Components Using a Martian Soil Simulant. Sci Rep 7, 1151 (2017). https://doi.org/10.1038/s41598-017-01157-w</ref><br />
<br />
==[[Embodied energy]]==<br />
Different types of brick require different amounts of energy to produce.<br />
{| class="wikitable"<br />
|+<br />
!Materials<br />
!Embodied energy<br />
(MJ/kg)<br />
!Density <br />
(kg/m3)<br />
!Production<br />
|-<br />
|Regolith<br />
|0,5<br />
|2000<br />
|Regolith compressed and combined with some form of cement<br />
|-<br />
|Clay<br />
|3<br />
|2000<br />
|Martian clay baked and fired<br />
|-<br />
|Plastic<br />
|80-100<br />
|900<br />
|Plastic from biomass or CO2+hydrogen reactions<br />
|-<br />
|Glass<br />
|15<br />
|2500<br />
|Silica, cleaned and with required additives<br />
|}<br />
<br />
==See Also==<br />
[[Universal bricks]]<br />
<br />
[[Category:Construction, Assembly, Maintenance]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140892Extreme Energy Cosmic Rays2024-03-03T01:56:47Z<p>RichardWSmith: /* Discussion */</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggestion that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle | The Oh My God particle]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140891Extreme Energy Cosmic Rays2024-03-03T01:56:00Z<p>RichardWSmith: /* Discussion */ fixed spelling mistake</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggestion that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle |The Oh My God particle]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140890Solar Cosmic Rays2024-03-03T01:50:19Z<p>RichardWSmith: /* Mitigation Strategies */ fixed grammar</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have time to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]] <br />
<br />
[[Extra Galactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140889Extreme Energy Cosmic Rays2024-03-03T01:46:17Z<p>RichardWSmith: Formatting</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggest that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle |The Oh My God particle]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140888Extreme Energy Cosmic Rays2024-03-03T01:45:00Z<p>RichardWSmith: Formatting</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggest that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle|The Oh My God particle]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Extreme_Energy_Cosmic_Rays&diff=140887Extreme Energy Cosmic Rays2024-03-03T01:43:32Z<p>RichardWSmith: New page.</p>
<hr />
<div>Extreme Energy Cosmic Rays are cosmic rays that have more than 50 Exa Electron Voltes (50 EeV). These are thought to be impossible, and no good explanation as to how they are created has been offered.<br />
<br />
==Discussion==<br />
Cosmic Rays with more than 50 EeV of energy are thought to slowly lose energy as they travel vast distanced between galaxies. If they travel about 160 million light years or more, quantum mechanical interactions with the Cosmic Microwave Background Radiation should bleed energy away from them. This is called the Greisen-Aztsepin-Kuzmin limit. (See this wikipedia article for more information. <ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>)<br />
<br />
However, we HAVE detected particles with more than this energy. Several ideas have been suggested how they can reach us, some of which break the laws of physics as we understand them. (So we need new physics!) One suggest that these particles are not protons or alpha particles but rather an iron nucleus, tho how something so heavy is accelerated so fast is hard to explain.<br />
<br />
The [[https://en.wikipedia.org/wiki/Oh-My-God_particle|Oh-My-God particle]] is a wiki page that describes the most powerful cosmic ray that we have ever detected.<br />
<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Extra_Galactic_Cosmic_Rays&diff=140886Extra Galactic Cosmic Rays2024-03-03T01:28:22Z<p>RichardWSmith: New page</p>
<hr />
<div>Extra Galactic Cosmic Rays are Cosmic Rays (CR) that are almost certainly too powerful to be created from sources inside our galaxy. Therefore, they are thought to come from vast distances. They are probably produced in quasars or active galactic nucleus.<br />
<br />
They have huge energies of quadrillion to quintillions of electron volts. This is a massive energy to be carried by a single particle. <br />
<br />
==Discussion==<br />
The upper limit for these particles is an energy of 50 exa electron volts (50 EeV), because particles going faster than this lose energy to the cosmic microwave background radiation. This is called the Greisen-Zatsepin-Kuzmin limit (GZK cutoff), thru quantum mechanical effects. (See this wiki article for more details.<ref>https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit</ref>) Note that the GZK cutoff only applies to particles which travel vast distances, ~160 million light years. There are no quasars within this distance and few active galactic nucleus this close.<br />
<br />
However, we have detected cosmic rays with higher than this energy which have not come from any direction close to an active galaxy. Thus we have found [[Extreme Energy Cosmic Rays]] for which we have no explanation as to their origins.<br />
<br />
These cosmic rays are so powerful that no conceivable radiation protection will help, save making bases kilometres below the surface of Mars. Since we are bombarded with these particles (their secondary radiation from colliding with air atoms high in our atmosphere) on the surface of Earth they will be ignored by Martian colonists exactly as we ignore them here on Earth.<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Galactic Cosmic Rays]]<br />
<br />
[[Extreme Energy Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Galactic_Cosmic_Rays&diff=140885Galactic Cosmic Rays2024-03-03T00:38:53Z<p>RichardWSmith: /* Origin */ Fixed sentence.</p>
<hr />
<div>Galactic Cosmic Rays (Galactic CR) are cosmic rays that do not come from the sun, but may have been created inside our galaxy. They may have low energies but range up to the millions or billions of electron volts. Cosmic Rays come from every direction in the sky, unlike Solar CR which come from one location (the sun).<br />
<br />
==Discussion==<br />
The focus of this discussion is on the radiation concerns of cosmic rays. The lower the energy, the easier they are to shield against. For example, low energy cosmic rays can be directed by the Earth's magnetic field and to impact at the polar regions. Higher energy cosmic rays move so fast, that they have not the time to be so redirected. Low energy Cosmic Rays (CR) are completely stopped by the Earth's atmosphere. High energy CR will explode on hitting Earth's air, and cause a cascade of secondary particles which can reach ground level, and even penetrate many meters below the Earth's surface.<br />
<br />
(Scientific experiments that wish to avoid Cosmic Rays (CR) are built in mines a couple km below the surface, or deep in Antarctic ice.)<br />
<br />
==Origin==<br />
If a Cosmic Ray hits a detector, we can not know where it came from. Did it come from the Milky Way, or some distant galaxy? There is no way to know. When we discuss Galactic CR, we are talking about Cosmic Rays that MIGHT have come from within our galaxy. From supernova shock waves, neutron star mergers, accretion disks from small black holes, massive Coronal Mass Ejections from super hot stars, and the like which exist inside our galaxy. Some Cosmic Rays are so powerful, that we think that they must be made in active galactic nucleus or quasars (see [[Extra Galactic Cosmic Rays]]) which are far from our galaxy.<br />
<br />
==Mitigation==<br />
Low energy particles can be stopped by the normal [[Radiation]] protection given to [[Solar Cosmic Rays]]. However, higher energy Galactic CR, fall into the energies which are largely stopped by the Earth's atmosphere, but are not stopped by Mars' thin atmosphere. Thus they are a real concern for Mars colonists. (For short term explorers, they will simply accept a couple years of higher radiation, similar to doses accepted by current long duration astronauts.) <br />
<br />
These medium energy Cosmic Rays (CR) are not stopped by magnetic fields (they don't spend enough time in them to be redirected any great distance, they just punch thru). So the only way to mitigate them is to have mass. If we don't have dozens of km of thick air, then we need water or soil between us and the sky. Generally we want to have at least a meter of water or half a meter of soil to bring radiation down to acceptable levels, tho double that value would be better (because people will spend time outside with less protection and we want the average dosage to be low). Some authors on this site, who prefer almost no radiation, suggest values up to 13 times greater than this minimum. (See [[Radiation]].) <br />
<br />
Note that the lower energy Galactic CR are pulled towards the sun's magnetic poles by the sun's magnetic field. So when the sun is at its solar maximum, we get lower doses of the low energy Galactic Cosmic Rays than when the sun is at solar minimum. (But then again, when the sun is active, we get more Solar CR.) This has little effect on high energy Galactic CR which quickly punch thru the Sun's magnetic field. (On Earth we get Cosmic Rays both during times of Solar Maximum and Solar Minimum.)<br />
<br />
Radiation that comes in sudden intense bursts is far more dangerous than a slow, steady trickle of radiation damage, because our bodies constantly, slowly repairs radiation damage. Galactic Cosmic Rays comes in a slow, steady trickle, so there is no need for a radiation storm shelter for sudden bursts of galactic CR. <br />
<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Galactic_Cosmic_Rays&diff=140884Galactic Cosmic Rays2024-03-03T00:37:27Z<p>RichardWSmith: New page.</p>
<hr />
<div>Galactic Cosmic Rays (Galactic CR) are cosmic rays that do not come from the sun, but may have been created inside our galaxy. They may have low energies but range up to the millions or billions of electron volts. Cosmic Rays come from every direction in the sky, unlike Solar CR which come from one location (the sun).<br />
<br />
==Discussion==<br />
The focus of this discussion is on the radiation concerns of cosmic rays. The lower the energy, the easier they are to shield against. For example, low energy cosmic rays can be directed by the Earth's magnetic field and to impact at the polar regions. Higher energy cosmic rays move so fast, that they have not the time to be so redirected. Low energy Cosmic Rays (CR) are completely stopped by the Earth's atmosphere. High energy CR will explode on hitting Earth's air, and cause a cascade of secondary particles which can reach ground level, and even penetrate many meters below the Earth's surface.<br />
<br />
(Scientific experiments that wish to avoid Cosmic Rays (CR) are built in mines a couple km below the surface, or deep in Antarctic ice.)<br />
<br />
==Origin==<br />
If a Cosmic Ray hits a detector, we can not know where it came from. Did it come from the Milky Way, or some distant galaxy? There is no way to know. When we discuss Galactic CR, we are talking about Cosmic Rays that MIGHT have come from within our galaxy. From supernova shock waves, neutron star mergers, accretion disks from small black holes, massive Coronal Mass Ejections from super hot stars, and the like which exist inside our galaxy. Some Cosmic Rays are so powerful, that we think that they must be made in active galactic nucleus or quasars (see [[Extra Galactic Cosmic Rays]] which are far from our galaxy.) <br />
<br />
==Mitigation==<br />
Low energy particles can be stopped by the normal [[Radiation]] protection given to [[Solar Cosmic Rays]]. However, higher energy Galactic CR, fall into the energies which are largely stopped by the Earth's atmosphere, but are not stopped by Mars' thin atmosphere. Thus they are a real concern for Mars colonists. (For short term explorers, they will simply accept a couple years of higher radiation, similar to doses accepted by current long duration astronauts.) <br />
<br />
These medium energy Cosmic Rays (CR) are not stopped by magnetic fields (they don't spend enough time in them to be redirected any great distance, they just punch thru). So the only way to mitigate them is to have mass. If we don't have dozens of km of thick air, then we need water or soil between us and the sky. Generally we want to have at least a meter of water or half a meter of soil to bring radiation down to acceptable levels, tho double that value would be better (because people will spend time outside with less protection and we want the average dosage to be low). Some authors on this site, who prefer almost no radiation, suggest values up to 13 times greater than this minimum. (See [[Radiation]].) <br />
<br />
Note that the lower energy Galactic CR are pulled towards the sun's magnetic poles by the sun's magnetic field. So when the sun is at its solar maximum, we get lower doses of the low energy Galactic Cosmic Rays than when the sun is at solar minimum. (But then again, when the sun is active, we get more Solar CR.) This has little effect on high energy Galactic CR which quickly punch thru the Sun's magnetic field. (On Earth we get Cosmic Rays both during times of Solar Maximum and Solar Minimum.)<br />
<br />
Radiation that comes in sudden intense bursts is far more dangerous than a slow, steady trickle of radiation damage, because our bodies constantly, slowly repairs radiation damage. Galactic Cosmic Rays comes in a slow, steady trickle, so there is no need for a radiation storm shelter for sudden bursts of galactic CR. <br />
<br />
<br />
==See Also==<br />
[[Solar Cosmic Rays]]<br />
<br />
[[Extra Galactic Cosmic Rays]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140883Solar Cosmic Rays2024-03-02T23:54:52Z<p>RichardWSmith: /* See Also */ fixed link</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]] <br />
<br />
[[Extra Galactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140882Solar Cosmic Rays2024-03-02T23:53:52Z<p>RichardWSmith: /* See Also */</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]] <br />
<br />
[[Intergalactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140881Solar Cosmic Rays2024-03-02T23:53:34Z<p>RichardWSmith: /* See Also */</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]] <br />
[[Intergalactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140880Solar Cosmic Rays2024-03-02T23:50:29Z<p>RichardWSmith: </p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
==See Also==<br />
[[Galactic Cosmic Rays]]<br />
[[Intergalactic Cosmic Rays]]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140879Solar Cosmic Rays2024-03-02T23:49:08Z<p>RichardWSmith: Added section on Terraforming</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==Effects of Terraforming==<br />
If Mars was to be given an artificial magnetic field (say by running a super conducting loop around the equator and pushing a current thru it) then Solar Cosmic Rays are weak enough that some of them will be directed to the poles reducing the radiation count in the low and mid latitudes.<br />
<br />
As Mars atmosphere gets thicker, proportionally more low energy Cosmic Rays will be stopped.<br />
<br />
Note that while terraforming will help protect against solar cosmic rays, it will have little effect against more powerful forms of cosmic rays.<br />
<br />
<br />
==See Also==<br />
[Galactic Cosmic Rays]<br />
[Intergalactic Cosmic Rays]<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140878Cosmic radiation2024-03-02T23:39:47Z<p>RichardWSmith: /* Point of origin */</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health. <br />
<br />
Cosmic rays come in a wide range of energies from lower energy ones from the sun, to more powerful ones from galactic sources, to the most powerful that can only be generated outside our galaxy.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
* kilo = 10^3 = 1,000 -- common name is thousand.<br />
* mega = 10^6 = 1,000,000 -- common name is a million.<br />
* giga = 10^9 = 1,000,000,000 -- common name is a billion.<br />
* tera = 10^12 = 1,000,000,000,000 -- common name is a trillion.<br />
* peta = 10^15 = 1,000,000,000,000,000<br />
* exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within (?) our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays than Mars' atmosphere. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140877Cosmic radiation2024-03-02T23:33:51Z<p>RichardWSmith: Made sentenced clearer and more accurate.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health. <br />
<br />
Cosmic rays come in a wide range of energies from lower energy ones from the sun, to more powerful ones from galactic sources, to the most powerful that can only be generated outside our galaxy.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
* kilo = 10^3 = 1,000 -- common name is thousand.<br />
* mega = 10^6 = 1,000,000 -- common name is a million.<br />
* giga = 10^9 = 1,000,000,000 -- common name is a billion.<br />
* tera = 10^12 = 1,000,000,000,000 -- common name is a trillion.<br />
* peta = 10^15 = 1,000,000,000,000,000<br />
* exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays than Mars' atmosphere. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140876Solar Cosmic Rays2024-03-02T23:26:50Z<p>RichardWSmith: Tidied up look, formatting.</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.<br />
<br />
==References:==</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140875Solar Cosmic Rays2024-03-02T23:26:14Z<p>RichardWSmith: Tidied up look, formatting.</p>
<hr />
<div>Solar Cosmic Rays (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==Frequency and Energies of Solar Storms==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==Mitigation Strategies==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
==References:==<br />
<br />
<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140874Solar Cosmic Rays2024-03-02T23:18:32Z<p>RichardWSmith: fixed formatting</p>
<hr />
<div>'''Solar Cosmic Rays''' (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).<ref>https://en.wikipedia.org/wiki/Coronal_mass_ejection</ref> They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
==FREQUENCY AND ENERGIES==<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. <ref>https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.</ref><br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
==MITIGATION STRATAGIES ==<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.</div>RichardWSmithhttp://marspedia.org/index.php?title=Solar_Cosmic_Rays&diff=140873Solar Cosmic Rays2024-03-02T23:16:09Z<p>RichardWSmith: New page discussing the least powerful CR.</p>
<hr />
<div>'''Solar Cosmic Rays''' (Solar CR) are high energy particles released by massive explosions on the sun called [Coronal Mass Ejections] (CME).[ref]https://en.wikipedia.org/wiki/Coronal_mass_ejection[/ref] They are not the normal solar wind which is easy to shield against, but much higher energy particles with far more penetrating power.<br />
<br />
---FREQUENCY AND ENERGIES---<br />
Coronal Mass Ejections (CME) are usually small and common. They can happen about once a week when the sun is least active, to a couple times a day when the sun is at the peak of its sunspot cycle. However, not all CME are aimed at Earth or Mars. If the explosion is on the far side of the sun facing way from us, it will have no effect on colonists. [ref]https://www.jpl.nasa.gov/nmp/st5/SCIENCE/cme.html#:~:text=CMEs%20often%20occur%20along%20with,to%20three%20CMEs%20per%20day.[/ref]<br />
<br />
The energy of solar cosmic rays varies widely, the lowest energy ones are from 10,000 electron volts to a couple hundred mega electron volts (~200,000). However, in the most powerful CME, about 1% of the time particles in the giga-electron volt range are detected.<br />
<br />
This is a huge range, the weakest particles are 100 million times less energetic than the most powerful ones. (Fortunately the very powerful ones are quite rare.)<br />
<br />
The thin Martian atmosphere provides significant protection against the weakest solar cosmic rays. However, space suits and Mars rovers should have radiation protection. Against the common Solar CR, this is just part of the day to day higher radiation to be found on Mars. However, on the rare cases when a powerful solar storm will hit Mars, mitigation strategies must be taken.<br />
<br />
--- MITIGATION STRATAGIES---<br />
We can optically detect the solar flares associated with Coronal Mass Ejections (CME), and can have several days of warning (for lower energy ones) to only hours of warning for the most powerful ones. Thus colonists on Mars' surface are likely to have warning to get into radiation shelters, if a CME is detected. <br />
<br />
Habitats on Mars will likely have normal radiation protection (say a meter of water or dirt above living quarters). But it would be wise to have a smaller volume with very high radiation protection as a storm shelter, which people can go into for the couple hour solar storm. People might crowd together and watch a movie or two during the solar storm.<br />
<br />
Note that if a CME happens at night, the colonists will be protected from the sun by the mass of the planet under them.<br />
<br />
A colonist in a rover far from a base, which is caught in the open at noon by a rare, very powerful CME is in trouble. They might stop, cover the top of the rover with sand bags (maybe not enough protection), then wait a couple hours UNDER the rover to maximize protection. Rovers might have a tiny storm shelter which people can lie in for a 2 or 3 hour solar storm. However, volume inside a rover is small, and there might not be room for such a storm shelter. A huge solar storm when a colonist is far from shelter is a real concern.</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140872Cosmic radiation2024-03-02T22:29:22Z<p>RichardWSmith: Organized sections better.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health. <br />
<br />
Cosmic rays come in a wide range of energies from lower energy ones from the sun, to more powerful ones from galactic sources, to the most powerful that can only be generated outside our galaxy.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
* kilo = 10^3 = 1,000 -- common name is thousand.<br />
* mega = 10^6 = 1,000,000 -- common name is a million.<br />
* giga = 10^9 = 1,000,000,000 -- common name is a billion.<br />
* tera = 10^12 = 1,000,000,000,000 -- common name is a trillion.<br />
* peta = 10^15 = 1,000,000,000,000,000<br />
* exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140871Cosmic radiation2024-03-02T22:26:02Z<p>RichardWSmith: /* Energies of Cosmic Rays: */ formatting</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
* kilo = 10^3 = 1,000 -- common name is thousand.<br />
* mega = 10^6 = 1,000,000 -- common name is a million.<br />
* giga = 10^9 = 1,000,000,000 -- common name is a billion.<br />
* tera = 10^12 = 1,000,000,000,000 -- common name is a trillion.<br />
* peta = 10^15 = 1,000,000,000,000,000<br />
* exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140870Cosmic radiation2024-03-02T22:24:51Z<p>RichardWSmith: /* Energies of Cosmic Rays: */ fixed formatting.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
* kilo = 10^3 = 1,000 common name is thousand.<br />
* mega = 10^6 = 1,000,000 common name is a million.<br />
* giga = 10^9 = 1,000,000,000 common name is a billion.<br />
* tera = 10^12 = 1,000,000,000,000 common name is a trillion.<br />
* peta = 10^15 = 1,000,000,000,000,000<br />
* exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140869Cosmic radiation2024-03-02T22:24:01Z<p>RichardWSmith: Discussed the range of energies of cosmic rays.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
It is worth discussing the RANGE of the energies of all of the different things being lumped into the category of Cosmic Rays. Look at the SI prefixes which we are using:<br />
kilo = 10^3 = 1,000 common name is thousand.<br />
mega = 10^6 = 1,000,000 common name is a million.<br />
giga = 10^9 = 1,000,000,000 common name is a billion.<br />
tera = 10^12 = 1,000,000,000,000 common name is a trillion.<br />
peta = 10^15 = 1,000,000,000,000,000<br />
exa = 10^18 = 1,000,000,000,000,000,000<br />
<br />
Therefore the most powerful cosmic rays are million * million * million times more powerful than the lowest energy ones. Lumping these all together is not helpful.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Terraforming&diff=140868Terraforming2024-03-02T21:52:59Z<p>RichardWSmith: Discussed faster ways to draw CO2 out of the atmosphere / biosphere.</p>
<hr />
<div>[[File:Logo-Mars-in-a-shell.jpg|thumb|The planet Mars under a global glas dome. This is certainly not an idea of terraforming, but it gives an idea of the dimensions of the topic.]]<br />
'''Terraforming''', or ''Earth-shaping'', is a theoretical process of modifying a planet's atmosphere to make it habitable for humans. In the case of Mars, terraforming would require first warming the planet, then artificial thickening of the atmosphere so pressure suits are not needed, [[water|ice]] melting to increase the H<sub>2</sub>O content of the atmosphere (creating [[clouds|water clouds]]), adding nitrogen as a buffer gas, and greatly increasing the [[oxygen|O<sub>2</sub>]] density to ultimately make the atmosphere breathable. <br />
<br />
Nicole Willett has written her own article on [[Terraforming Mars]].<br />
<br />
==Mars and the "Triple Point" of water== <br />
<br />
[[Image:Phase_diagram_water.png|thumb|right|200px|The phase diagram for water, clearly displaying water's [[triple point]].]] <br />
<br />
Presently, [[water|ice]] on Mars usually [[sublimation|sublimes]] (rather than melts) as the atmospheric pressure is so low, ice bypasses the liquid phase when heated. Sublimation occurs allowing ice to turn directly into gas (steam). One of the main challenges for future terraforming efforts would be to increase the atmospheric pressure significantly so water can exist as a liquid on the surface of Mars. The atmospheric pressure and ambient temperature will therefore need to be greater than the [[triple point]] of water (thereby existing as ice, liquid and gas). This is just above 0C and 600 Pa. Mars atmospheric pressure is already above 600 Pa. However, close to the triple point, water takes very little energy to turn into a gas, so higher pressures would be required in practice.<br />
<br />
==Methods==<br />
Using giant mirrors to reflect light on to Mars would help warm Mars by increasing its insolation. Statites (stationary satellites held up by light pressure) have been suggested to beam light to the north and south poles of Mars. Others have suggested mirrors in sun synchronous orbits to beam light onto the terminator (which would brighten both dawn and dusk). An advantage of space mirrors is that they could be adjusted to direct light and heat to where it is most needed. (e.g. to the northern hemisphere in norther winter, and the Southern Hemisphere in southern winter.)<br />
<br />
Mars could be warmed up using [[Super Greenhouse Gases]] such as perfluorocarbons, which are stable in the atmosphere for long periods of time. Since this method makes the heat which reaches Mars remain longer, it is very useful, and makes other strategies work better. (For example, space mirrors heating effect would be greater if the atmosphere held that heat longer.) It is likely that any plan to terraform Mars will use some [[Super Greenhouse Gases]].<br />
<br />
Other super greenhouse gasses include [[sulfur hexafluoride]] and 1,1,1-Trichloro ethane. These are very stable and highly effective greenhouse gasses. Use of such gasses to warm the atmosphere would allow the Carbon dioxide frozen into the polar caps and some of the water to evaporate adding to the mass of the atmosphere. If 4 hundredths of a microbar of manufactured greenhouse gas is needed to warm Mars to the point of runaway greenhouse effect, then a mass of manufactured greenhouse gasses equal to about 5.73 times the cargo capacity of the Edmund Fitzgerald (26,000 tonnes) every week for twenty years (about 150 million tonnes) would be required for the project. (Other estimates suggest a somewhat higher amount would be required to make up for the break up of these gases by ultraviolet light. See the [[Super Greenhouse Gases|Super Greenhouse Gas]] page for more discussion.)<br />
<br />
Regular [[greenhouse gases]] such as water or CH4 (methane) will build up as Mars warms and the air pressure increases. Methane is produced by life, so even simple life (anorexic bacteria) will help terraform the planet, making a positive feedback loop.<br />
<br />
Using nuclear bombs to vaporize the southern carbon dioxide (CO2) ice cap is now thought to be ineffective. (The CO2 would simply freeze out again.) NASA researcher, Chris McKay, has pointed out that all the nuclear bombs on Earth only equal the energy of 1/2 an hour of Martian sunlight. Global warming is caused by retaining more of the Sun's heat, not with nuclear bombs.<br />
<br />
However, using bombs to free [[nitrogen]] from nitrate deposits might be a useful technique. Martin J. Fogg in his Terraforming text book suggests using 'clean pipe' fusion bombs triggered with shaped explosives (rather than fission bomb triggers), to free nitrogen and ice from deep deposits, without the fallout of the fission bomb triggers. <br />
<br />
<br />
A life supporting atmosphere needs to contain a "buffer gas", such as nitrogen. Mars is currently lacking in nitrogen, but nitrogen could be sourced from Venus, Saturn's moon Titan, or from comets. (Note that it is likely that Mars has nitrogen in its soil, see [[Atmospheric loss]].) Nitrogen is transparent to heat radiation, so it is not a greenhouse gas. <br />
<br />
Curiosity rover detected nitrates in the soil of Mars. If widespread, this is very good news for terraformers, as the nitrogen is biologically available and if moved into the atmosphere, would give Mars approximately 0.3 Bar of Nitrogen partial pressure. <ref>https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL072199 - Measurements of Nitrates and Perchlorates in Martian soil</ref><br />
<br />
==Pioneer Organisms==<br />
The first creatures to live on the natural Mars landscape would be bacteria. (See [[Bacteria Colonists]].) Cyanobacteria (aka blue-green algae), live in water and would produce oxygen. They can live under ice if the ice cover is not too thick.<br />
<br />
Certain organisms, such as [[archaea]], [[lichen]], and [[tardigrades]] have been proven capable of surviving for some time in extreme environments, such as the vacuum of space. They could gain a foothold on the Martian surface after minimal terraforming. The byproducts of their metabolism would contribute to the terraforming efforts.<br />
<br />
==Calculations==<br />
*To increase Martian air pressure to 25 kPa, 2500 kg per m2 of atmosphere would be required. This is equivalent to a layer of about 1,5m of solid CO2. However, since this is not available on Mars, the existing CO2 would need to be supplemented by an inert gas, such as nitrogen, that might be sourced from Venus, comets or the outer solar system such as Saturn's moon titan. To round out the use of existing CO2, at least 2-3e17 kg of nitrogen would need to be imported. If the importation deltaV was 10 km/s, then the entire amount solar energy falling on Mars for about 20 years would be required to move the nitrogen to Mars. <br />
**If importing from Venus, most of the energy would be spend moving the nitrogen up to Venus low orbit (9.2 km/s), for a total deltaV of about 15 km/s.<br />
**If imported from Titan, the total deltaV would be about 12 km/s.<br />
**If imported from Ceres, the total deltaV might be 8 km/s. So asteroids in the outer belt (richer in volatiles) might be an interesting early source of nitrogen.<br />
<br />
<br />
*The water available on Mars in frozen form is already sufficient for a significative ocean.<br />
<br />
*Drawing down the CO2 partial pressure is likely to be done by biological carbon sequestration. Carbon sequestration in a biosphere might store between 100 to 300 tons of carbon per hectare, or 10-30 kg/m2 (ref). Carbon sequestration would consume CO2 and free oxygen, increasing its concentration in the atmosphere. The carbon in the Martian atmosphere masses about 6.5e15 kg. This would be enough to supply 2 to 6e14 m2 of land with the required sequestrated carbon. As Mars' surface is only 1.44e14m2, the biosphere could absorb most, but not all, of the carbon. Additional CO2 would be stored in a Martian ocean, or as carbonates. Therefore excess CO2 is probably not a problem, the problem is adding the required buffer gas, most likely nitrogen. Some CO2 would need to remain in the atmosphere to run the CO2 cycle. <br />
<br />
Note that covering the entire planet with soil, and then adding carbon to it is very slow. Fogg has suggested that growing trees, and moving the lumber outside the biosphere (say by burying it deep, or placing it above the atmosphere in the Olympus Mons caldera) would be a much faster way of drawing down CO2 levels, taking only thousands of years.<br />
<br />
==Long term prospects==<br />
<br />
The ultimate results of terraforming are disputed. Terraforming may have only a temporary effect, even if the effect lasts for some hundred or thousand years. Eventually, the [[solar wind]] may carry away most of the new atmosphere due to the insufficient [[magnetosphere|magnetic field]]s of Mars, though this would take hundreds of millions of years. (See [[Atmospheric loss]] for more details.)<br />
<br />
It has been suggested that the cost of terraforming a planet would be prohibitive. However, to a growing population on the surface of that planet it would most likely be considered a normal colonial function to ensure that daily colonial endeavours have a positive effect on the atmosphere. Also note that industry will naturally produce greenhouse and super greenhouse gases for 'free', so some terraforming is likely to happen just from having a human presence on Mars.<br />
<br />
Artificial magnetic fields might also be created around Mars to reduce atmospheric losses to space. And the solar system contains sufficient resources to replenish Martian atmosphere indefinitely, but at a significant energy cost. Building space habitats might be a more practical long term objective for human occupation of space. (Altho space habitats leak air faster, by many orders of magnitude, than atmospheric loss from solar wind sputtering.)<br />
<br />
==Partial terraforming==<br />
<br />
{| class="wikitable" align="right" style="margin-left:1em;"<br />
|+Present gas abundance on Mars and required limits for plants and humans<br />
|-<br />
!Parameter!!Mars<ref name="Abundance">Mahaffy, P. R.; Webster, C. R.; Atreya, S. K.; Franz, H.; Wong, M.; Conrad, P. G.; Harpold, D.; Jones, J. J.; Leshin, L. A.; Manning, H.; Owen, T.; Pepin, R. O.; Squyres, S.; Trainer, M.; Kemppinen, O.; Bridges, N.; Johnson, J. R.; Minitti, M.; Cremers, D.; Bell, J. F.; Edgar, L.; Farmer, J.; Godber, A.; Wadhwa, M.; Wellington, D.; McEwan, I.; Newman, C.; Richardson, M.; Charpentier, A. - ''Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover'', Nature 341, pp. 263-266. DOI:10.1126/science.1237966</ref>, mbar!!Plants<ref name="Making_Mars_habitable">Christopher P. McKay, Owen B. Toon & James F. Kasting - ''Making Mars habitable'', Nature 352, pp. 489-496. DOI:10.1038/352489a0</ref>, mbar!!Humans, mbar<br />
|-<br />
|Total pressure||0.30-11.55 (6 average)||>10||>250<br />
|-<br />
|Carbon dioxide (CO<sub>2</sub>)||0.29-11.09 (5.76 average)||>0.15||<0.5<br />
|-<br />
|Nitrogen (N2)||0.01-0.22 (0.114 average)||>1-10||-<br />
|-<br />
|Oxygen (O<sub>2</sub>)||<0.015||1||>130<br />
|-<br />
|Argon (Ar)<br />
|0.09<br />
|0<br />
|0<br />
|-<br />
|Carbon Monoxide (CO)<br />
|0.004<br />
|0<br />
|0<br />
|-<br />
|Water (H2O)<br />
|0.0018<br />
|~10<br />
|~10<br />
|}<br />
<br />
While full terraforming to make Mars atmosphere suitable for breathable condition for humans can take many generations, transformations to the atmosphere suitable for plants could be faster. Current requirements for plants to grow on Mars are based on atmospheric pressure. Mars polar caps have enough CO<sub>2</sub> to provide 100 mbar (10 kPa) additional atmospheric pressure to the existing 6 millibars. This would probably be enough to create sustainable growth condition for plants.<br />
<br />
The first job will be to add bacteria. Many types can live at Mars' current pressures, but they need liquid water, and thus the temperature must be increased. A key goal is to warm the planet by about 20 degrees C. This will cause the poles to evaporate, releasing massive amounts of CO2, and a good deal of water. The increased pressure will result in liquid water appearing for short times (typically it will freeze at night). But even transient water is enough for bacteria to start spreading. See [[Bacteria Colonists]] for more information.<br />
<br />
To add enough pressure to make using pressure suit unnecessary for humans, atmospheric pressure needs to rise to at least 100 mbar (10 kPa) or ~10% of Earth atmospheric pressure. <br />
<br />
To make it so a breathing mask is not required, the pressure needs to be at least 250 mbar (25% Earth's pressure), AND the oxygen partial pressure must be increased, AND the carbon dioxide partial pressure must be reduced. Drawing down the CO2 partial pressure is likely to be done by biological carbon sequestration. Carbon sequestration in a biosphere might store between 100 to 300 tons of carbon per hectare, or 10-30 kg/m2 (ref). Carbon sequestration would consume CO2 and free oxygen, increasing its concentration in the atmosphere.<br />
<br />
To get to a breathable atmosphere, a combination of oxygen, and various other gases must be generated. This might be composed of 118 mbar of nitrogen, 1 mbar of argon and neon, 1 mbar of water vapour and 130 mbar of oxygen (minimal requirement oxygen pressure). Note that the CO2 must be at trace levels for animals to breath. CO2 of 0.05% is the maximum we would want for a breathable atmosphere. (Argon and neon are not needed for life, but can act as a buffer gas.)<br />
<br />
We would want to increase CO2 partial pressure to warm the planet, but would have to later draw down this CO2 level if we wish to make the planet habitable for animals.<br />
<br />
Note that a partially terraformed world is still of use to humans. If we were to increase the pressure of the planet to 80 millibars, that is not enough for people to go on the surface with oxygen masks; they would need a pressure suit over most of the planet. But the LOWEST areas of the planet (e.g. the northern plains and Hellas Basin), would have high enough pressure to allow colonists to dispense with space suits and move about on the surface with simple gas masks. Further, the radiation from space, and solar UV would be reduced. (Not to Earth levels of safety, but better than current conditions.) Terraforming does not have to be 100% complete, to give safety and economic benefits to the habitants.<br />
<br />
[[Paraterraforming]] is a subset of terraforming where terraforming takes place inside huge structures which cover some fraction of the planet's surface.<br />
<br />
==Ethics of Terraforming==<br />
This seems very straightforward to me (Rick). The universe is FILLED with sterile rocks. Life is rare and precious. Adding another world where life can live for millions or billions of years is a noble act of the highest order. Perhaps the 'purpose' of intelligent life is to spread life in all its forms across space.<br />
<br />
<br />
==Books on Terraforming==<br />
"Terraforming: Engineering Planetary Environments", by Martin J. Fogg, ISBN: 1-56091-609-5, is a highly detailed textbook on the subject. It is very hard to find. Perhaps the Mars Society could update it and republish it.<br />
<br />
"New Earths: Restructuring Earth and Other Planets", by James Edward Oberg, ISBN: 0-8117-1007-6. <br />
<br />
"Terraforming: The Creating of Habitable Worlds", by Martin Beech, ISBN: 978-0-387-09795-4.<br />
<br />
==References==<br />
<references /><br />
<br />
x- https://cca-reports.ca/wp-content/uploads/2021/03/Carbon-Sinks_EN_CH-3_Forests.pdf<br />
[[category:Terraforming]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Low_gravity&diff=140846Low gravity2024-02-06T18:50:18Z<p>RichardWSmith: Made sentence clearer.</p>
<hr />
<div>Mars' surface gravity is 3.711 meters / second^2, or about 38% of Earth's gravity.<br />
<br />
There is no medical evidence for the effects on Mars' [[gravity]] on Earth life. Although we could simulate Mars' gravity on the International Space Station using a centrifuge, (with some mice in a cage for example), this experiment has never been done. Plants have been grown successfully in zero gee, so it is likely they would also be viable in 38% gee.<br />
<br />
==Long term medical effects of 38% gravity==<br />
As of 2024, no studies have researched this question. Once we have real data, please update this section.<br />
<br />
==Short term medical effects of 38% gravity==<br />
People with bad knee and hip joints may find Martian gravity to be a boon. In the far future, Mars might be seen as an attractive retirement location for that reason. (Tho Luna with 1/6 of Earth's gravity may be even more attractive.)<br />
<br />
==Martian gravity in fiction==<br />
<br />
<br />
==Increasing Gravity Inside Long Term Mars Habitations==<br />
There is a simple way to increase gravity within a major base on Mars... A centrifuge.<br />
<br />
The formula for centripetal force is:<br />
<br />
a = r(2 PI / T)^2. (a = acceleration, T = Time to rotate once, r = radius.) <br />
(Note the acceleration only needs to be ~62% of Earth's gravity because we will add Mars' current gravity to this acceleration.)<br />
<br />
So let's say we make an underground hyper loop railway on a circular track on an angle facing inwards (so when it is at speed, the gravity of the railcar plus Mars' gravity faces directly down to the floor of the car).<br />
<br />
If this circular track was 500 meters in diameter, then the car would have to go around the loop every 57 seconds, (say one RPM to round off). The hyper loop railway would have to go 55 meters per second, or 198 km/hour.<br />
<br />
The main reason to make it a hyper-loop is to avoid wear on the wheel's bearings. This speed is doable with Earth trains using today's tech, which have to fight thru Earth's air pressure. (Japan's bullet trains go 320 km/h for example.)<br />
<br />
Assuming the train is 100% as long as the track, and that it is two meters wide, then there is 0.684 square kilometres of area for people to exercise or sleep in. If we make the train 3 stories high, then this area triples.<br />
<br />
If we find that there are no long term ill effects at, say, 0.8 gees of gravity, the speed of the train could be lowered. Alternately the radius could be increased (giving us more living area), without increasing the speed.<br />
<br />
IF, and only if, we find that low gravity is a problem, then people could work 8 hours a day in the low gravity factories or farms. Then live and sleep in an underground habit at Earth gravity. Assuming it is underground, this would also reduce the radiation dose.<br />
<br />
===Eureka Settlement Proposal:===<br />
A [[Gravity|rotating settlement habitat]] is proposed [[Gravity|here]]. The Eureka <ref>https://macroinvent.com/wp-content/uploads/2019/03/Eureka-Mars-Settlement-Concept.pdf</ref>space Settlement was proposed for the [[Mars Colony Design Contest|2019 Mars society design contest.]]<br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Virus&diff=140845Virus2024-01-29T17:32:44Z<p>RichardWSmith: Mentioned that virus' are parasitic. No discussion if they are 'alive'.</p>
<hr />
<div>A virus is a parasitic [[Biology|form of life]] that can live only inside a living cell. (It hijacks the cell's molecular machinery to reproduce itself.) With respect to Mars this means that if there are no native Martian microbes, there are no native Martian Viruses either.<br />
<br />
Viruses will come with humans to Mars and be part of a settlement [[Biology|biological system]].<br />
<br />
{{stub}}<br />
<br />
[[Category:Health and Safety]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Martian_weather&diff=140844Martian weather2024-01-29T17:29:12Z<p>RichardWSmith: Added link.</p>
<hr />
<div>Martian weather is linked to the planet's inclination and to the planet's orbital eccentricity. See [[Atmosphere]] for a higher level view. The Wikipedia: [[w:Climate_of_Mars|Climate of Mars]] page is very complete.<br />
<br />
==Impact of weather for a Martian settlement==<br />
<br />
===Solar power availability===<br />
Local dust storms<br />
<br />
Global dust storms<br />
<br />
===Design temperatures===<br />
At the [[InSight Mission|Insight]] landing position (4.502 °N, 135.623 °E), quite close to the Martian equator, the temperature at Mars' surface has a wide daily range of 70 to 80°C, oscillating between maximums of 0°C to 10°C above during the day and -80 to -110°C at night.[https://mars.nasa.gov/insight/weather/] This is true of most of the Martian surface. Therefore it may be interesting to design [[cooling]] system for Mars settlements to profit from this swing by using thermal reservoirs to favor heat release at night.<br />
<br />
The average surface temperature is -68°C. With an average interior design temperature of 22°C, Mars settlements insulation systems may be designed for an average temperature difference of 90°C, with peak heating loads at 130°C of temperature difference(deltaT) and minimum loads of about 0°C deltaT.<br />
<br />
At these temperatures, care must be taken to use materials that will not suffer from an eventual [[w:Glass_transition|glass transition]]. Most plastics or polymers at the extreme low temperatures may change from flexible to glasslike, become brittle and fail. Heated garages, either with infrared lighting of enclosed atmospheres may be an option for some equipment during the night. Sealant around windows or gaskets for piping and airlocks may loose their properties as well.<br />
<br />
Coolants will also be affected by the temperature. Below -60°C, all glycol coolants, ethylene or propylene glycols, will freeze, and the water will expand and may rupture piping.<br />
<br />
Effect of latitude<br />
<br />
Northern hemisphere<br />
<br />
Southern hemisphere<br />
<br />
Influence of polar ice caps<br />
<br />
Influence of Hellas basin<br />
<br />
==References==<br />
Wikipedia: [[w:Climate_of_Mars|Climate of Mars]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140843Cosmic radiation2024-01-29T07:28:06Z<p>RichardWSmith: /* Thinking about comic rays: */ Fixed a typo.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5 times better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Starship&diff=140842Starship2024-01-29T01:39:36Z<p>RichardWSmith: Pointed out that the reduction of cost to orbit is a key advantage of Starship.</p>
<hr />
<div>[[File:Starship mirror2.jpg|alt=|thumb|The December 2019 Starship-Super Heavy launch stack]]<br />
'''Starship''' is the name of the 2019 version of the second stage of the [[SpaceX]] reusable super heavy lift vehicle, resting upon the [[Booster|Super Heavy]] booster. The term "Starship" may also be used to refer to the complete stack of both stages. SpaceX’s Starship spacecraft and Super Heavy rocket (collectively referred to as Starship) represent a fully reusable transportation system designed to carry both crew and cargo to Earth orbit, the Moon, Mars and beyond. Starship will be the world’s most powerful launch vehicle ever developed, with the ability to carry in excess of 100 metric tonnes to Earth orbit. Starship will enter Mars’ atmosphere at 7.5 kilometers per second and decelerate aerodynamically. The vehicle’s heat shield is designed to withstand multiple entries, but given that the vehicle is coming into Mars' atmosphere so hot, we still expect to see some ablation of the heat shield (similar to wear and tear on a brake pad). The engineering video below simulates the physics of Mars entry for Starship.<ref>[https://www.spacex.com/vehicles/starship/]</ref><br />
<br />
If SpaceX is able to make this ship work, with rapid turnaround, the cost of launching a kg into Low Earth Orbit will decrease at least ten fold. This will make all space projects (including Mars missions) much cheaper.<br />
<br />
==Development history==<br />
<br />
===2016 Interplanetary Transportation System===<br />
The origins of Starship are rooted in the Interplanetary Transportation System. This architecture was revealed in a 2016 speech by [[Elon Musk]] at the [[International Astronomical Congress]].<ref>Musk, Elon. 2016. ''[https://www.youtube.com/watch?v=H7Uyfqi_TE8 Making Humans a Multiplanetary Species]''. Guadalajara, Mexico.</ref> The concept was conceived as a two-stage spacecraft able to be reused a thousand times and to hold crews of over a hundred people with its primary intent to send people to Mars. The concept would depend upon tanker ships and orbital refueling, and it would extensively utilize [[in-situ resource utilization]] to produce the methane fuel required for the return voyage to Earth.<ref name=":0">"[http://spaceflight101.com/spx/ Interplanetary Transport System]". n.d. Spaceflight101.com. Accessed January 4, 2020.</ref><br />
<br />
The design was immense, with a twelve meter diameter and depended upon forty-two methane [[Raptor engine|Raptor engines]] on the booster alone, allowing it to produce thrust of thirteen-thousand metric tons. The stacked system would stretch up one-hundred-twenty-two meters into the sky. Upon stage separation, the booster would return to the launch site, landing propulsively on the launch mounts so that it could quickly be refueled and again flown. The second stage, which in some launches would include a habitat, had nine additional Raptor engines to accelerate the ship to Low Earth Orbit. In order to continue a trip to Mars, the second stage would have to be refueled by one or more tankers.<ref name=":0" /><br />
<br />
The proposal of the carbon fiber launch vehicle came with an estimated necessary cost of investment of ten billion dollars by Elon Musk, who suggested that a massive public-private partnership might be the best option for the vehicle. The original timeline of the proposal called for structures and propulsion development to be completed in 2019, when ship testing and orbital testing where to begin. Orbital testing was to be completed in late 2022, and shortly thereafter Mars flights were to begin.<ref name=":0" /> <br />
<br />
Musk acknowledged that this timeline was incredibly ambitious, but he believed that it was not ''too'' unreasonable. Musk took pride in announcing that two components of the system had already been built and were undergoing testing: the twelve-meter carbon fiber tank to store oxidizer in the second stage<ref>"[https://twitter.com/spacex/status/780859793443401728?lang=en First Development Tank for Mars Ship]". 2016. Twitter. September 27, 2016.</ref><ref>Mitchell, Jacob. 2016. "[https://twitter.com/JandCandO/status/780862729204723713 Here Is the inside of This Tank for You Guys!]" Twitter. September 27, 2016. </ref> and the first development versions of the Raptor methane full-flow staged combustion engine.<ref>Musk, Elon. 2016. "[https://twitter.com/elonmusk/status/780275236922994688 SpaceX Propulsion Just Achieved First Firing of the Raptor Interplanetary Transport Engine]". Twitter. September 26, 2016.</ref> Initial tests of the carbon fiber tank proved to be successful, with Musk noting that his company had not "seen any leaks or major issues" when testing the tanks with cryogenic propellent.<ref>Milberg, Evan. 2016. "[http://compositesmanufacturingmagazine.com/2016/11/spacex-successfully-tests-carbon-fiber-tank-mars-spaceship/ SpaceX Successfully Tests Carbon Fiber Tank for Mars Spaceship]". Composites Manufacturing. November 29, 2016.</ref> After heavy testing, the tank was destroyed in February 2017.<ref>"[https://www.reddit.com/r/spacex/comments/5ul1du/remains_of_the_its_composite_tank_in_anacortes_wa/ Remains of the ITS Composite Tank in Anacortes, WA]". 2017. r/SpaceXLounge on Reddit. February 17, 2017. </ref><br />
<br />
===2017 Big Falcon Rocket===<br />
Over the course of a year, Musk and SpaceX recognized that a smaller, more feasible system was necessary to be pursued. Musk revealed the scaled-back design at the 2017 International Astronomical Congress<ref>Musk, Elon. 2017. ''[https://www.youtube.com/watch?v=tdUX3ypDVwI Making Life Multiplanetary]''. Adelaide, Australia.</ref> almost exactly a year after the original unveil of the system. Musk also announced that the working name for the spacecraft was BFR, officially the Big Falcon Rocket. The height of the two-stage craft was reduced to one-hundred-six meters, and the diameter was reduced to nine meters.<ref>Dodd, Tim. 2017. "[https://everydayastronaut.com/2017-bfr-vs-2016-its/ 2017 BFR vs 2016 ITS]". Everyday Astronaut. September 29, 2017.</ref><br />
<br />
===2018 Starship-Super Heavy===<br />
This version was presented by Elon Musk during the announcement of Yusaku Maezawa's Dear Moon project, as an evolution of the BFR/BFS concept and Interplanetary Transportation System (ITS) concepts. It had three aerodynamic fins.<br />
<br />
===2019 Starship-Booster===<br />
Originally planned to be constructed of carbon fiber composite, it was changed to a Stainless Steel design in January 2019 .<ref>Popular Mechanics article [https://www.popularmechanics.com/space/rockets/a25953663/elon-muhttps://www.popularmechanics.com/space/rockets/a25953663/elon-musk-spacex-bfr-stainless-steel/sk-spacex-bfr-stainless-steel/]</ref><br />
The configuration was also changed to 4 adjustable flaps, or winglets, depending on nomenclature, two at the rear and two at the front.<br />
<br />
{| class="wikitable"<br />
|+<br />
Comparison of various iterations<br />
!<br />
!2016 ITS<br />
!2017 BFR<br />
!2018 Super Heavy-Starship<br />
!2019 Super Heavy-Starship<br />
|-<br />
|Iteration announced<br />
|27 Septemer 2016<br />
|<br />
|<br />
|<br />
|-<br />
|Stack height<br />
|122 m<br />
|106 m<br />
|118 m<br />
|118 m<br />
|-<br />
|– First stage height<br />
|<br />
|58 m<br />
|63 m<br />
|68 m<br />
|-<br />
|– Second stage height<br />
|<br />
|48 m<br />
|55 m<br />
|50 m<br />
|-<br />
|Diameter †<br />
|12 m<br />
|9 m<br />
|9 m<br />
|9 m<br />
|-<br />
|Principle material<br />
|Carbon fiber<br />
|Carbon fiber<br />
|Carbon fiber<br />
|301 Stainless steel<br />
|-<br />
|First stage thrust<br />
|128 MN<br />
|48 MN<br />
|<br />
|72 MN<br />
|-<br />
|Mass to Low Earth Orbit<br />
|300 t<br />
|150 t<br />
|100 t<br />
|100 t<br />
|-<br />
|Engines<br />
|51 Raptors<br />
|47 Raptors<br />
|<br />
|37 Raptors<br />
|-<br />
|– First stage engines<br />
|42 Raptors<br />
|31 Raptors<br />
|<br />
|31 Raptors<br />
|-<br />
|– Second stage engines<br />
|9 Raptors<br />
|2 Sea-level Raptors<br />
4 Vacuum Raptors<br />
|7 Sea-level Raptors<br />
|6 Raptors<br />
|-<br />
|Propellant capacity<br />
|<br />
|3625* t<br />
|<br />
|4500 t<br />
|-<br />
|– First stage capacity<br />
|<br />
|2525* t<br />
|<br />
|3300 t<br />
|-<br />
|– Second stage capacity<br />
|<br />
|1100 t<br />
|<br />
|1200 t (940t LOX, 260t CH4)<br />
|-<br />
|Pressurized volume<br />
|<br />
|825 m³<br />
|1000 m³<br />
|<br />
|-<br />
|Principle sources<br />
|<br />
|<ref>SpaceX. "[https://www.spacex.com/sites/spacex/files/making_life_multiplanetary-2017.pdf Slideshow: Making Life Multiplanetary]". 2017. </ref><ref>"[http://spacelaunchreport.com/bfr.html#config SpaceX Super Heavy/Starship Components]". 2019. Space Launch Report. December 9, 2019.</ref><br />
|<br />
|<ref>"[http://web.archive.org/web/20191230093531/https://www.spacex.com/starship Starship]". SpaceX. 2019. </ref><br />
|-<br />
| colspan="5" |* Indicates that this number is unofficial<br />
† Diameter has always been the same for the first and second stages<br />
|}<br />
<br />
==Characteristics of Starship==<br />
*85-120 tonnes mass, 9m diameter, 100-150 tonnes of payload to LEO, 100-150 tonnes to Mars. These are target values, the lower the mass of the vehicle, the higher the payload mass will be. Payload volume of 800-1000 m3, depending on Starship length.<ref>https://www.spacex.com/starship</ref><br />
<br />
*3 vacuum Raptor engines with 380s ISP and 3 (or six) atmospheric Raptor engines with 330s ISP. Nominal thrust of 2000 kN, (200 tonnes of force per engine) These numbers are subject to change as the engine and the vehicle concepts are under development.<br />
<br />
*120-160 day transportation time to Mars, using [[Aerobraking|aerocapture]] at Mars.<br />
<br />
*Fully reusable, rapid turnover and low maintenance vehicle. <br />
<br />
*Up to 100 passengers to Mars, although this has not been demonstrated yet by SpaceX.<br />
<br />
==Enabling technologies==<br />
The fundamental enabling technology of the Starship is [[Landing on Mars|supersonic retro propulsive]] landing on Mars. The use of supersonic retro-propulsion in a critical phase of the Mars entry path allows the vehicle to land heavier payloads that previously thought possible. Although the exact details are not public, the current SpaceX Falcon 9 booster rocket has done flight tests that would confirm the flight path. <ref>AEROTHERMAL ANALYSIS OF REUSABLE LAUNCHER SYSTEMS DURING RETRO-PROPULSION REENTRY AND LANDING [https://elib.dlr.de/120072/1/00040_ECKER.pdf]</ref><br />
<br />
A second enabling technology is reusability of the booster and of the Starship. This greatly reduces mission cost compared to single use designs and allows for high flight rates.<br />
<br />
A third enabling technology is the capacity of refueling the starship in orbit. This changes the requirements to Reach Mars from a high capacity system to a high flight rate system.<br />
<br />
A fourth enabling technology is the use of methane as fuel, than can be provided by In-situ resources production systems on Mars, and therefore allow for the re-use of the spaceship. <br />
<br />
A fifth technology is a robust heat shield for Mars and Earth entry. This allows for fast re-use and lower costs, but also for faster transit times, reducing the radiation exposure to travelers. The Spaceship is not necessarily intended to use low energy Hohmann transfer orbits, but higher velocity orbits. These have lower transit times but leave the vehicle with significant velocity when it reaches Mars or Earth. The Starship must then use direct entry and aerodynamic braking to shed the kinetic energy from the extra velocity. More conservative Hohmann transfer orbits may be used for the first flights. <br />
<br />
A sixth enabling technology is the use of stainless steel for the rocket body. This has allowed SpaceX to develop the vehicles using rapid prototyping and iterative methods, at the possible cost of reduced payload performances. <br />
<br />
==Launch pads==<br />
Two launch areas have been built or are under construction. One in Texas, one in Florida. The launch towers that service the vehicle stack use mechanical arms to move the vehicles, and are projected to be used to catch the vehicles at landing time, reducing the mass of the vehicles but adding a requirement for very precise position control at landing.<br />
<br />
==Flightpath==<br />
The NASA Ames research center trajectory browser can be used to explore transit times to Mars and other bodies in the Solar System. [https://trajbrowser.arc.nasa.gov/traj_browser.php Trajectory browser]<br />
<br />
==Point to point==<br />
A future use of the Starship as a point to point launch system has been proposed by SpaceX. Large production volumes and a high flight rate would reduce the price of Starship production, and therefore the cost of transportation to Mars.<br />
<br />
== See also ==<br />
[[List of Launch Systems and Vendors|List of launch systems]]<br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Low_gravity&diff=140841Low gravity2024-01-29T01:21:19Z<p>RichardWSmith: Updated the date.</p>
<hr />
<div>Mars' surface gravity is 3.711 meters / second^2, or about 38% of Earth's gravity.<br />
<br />
There is no medical evidence for the effects on Mars' [[gravity]] on Earth life. Although we could simulate Mars' gravity on the International Space Station using a centrifuge, (with some mice in a cage for example), this experiment has never been done. Plants have been grown successfully in zero gee, so it is likely they would also be viable in 38% gee.<br />
<br />
==Long term medical effects of 38% gravity==<br />
As of 2024, no studies have researched this question. Once we have real data, please update this section.<br />
<br />
==Short term medical effects of 38% gravity==<br />
People with bad knee and hip joints may find Martian gravity to be a boon. In the far future, Mars might be seen as an attractive retirement location for that reason. (Tho Luna with 1/6 of Earth's gravity may be even more attractive.)<br />
<br />
==Martian gravity in fiction==<br />
<br />
<br />
==Increasing Gravity Inside Long Term Mars Habitations==<br />
There is a simple way to increase gravity within a major base on Mars... A centrifuge.<br />
<br />
The formula for centripetal force is:<br />
<br />
a = r(2 PI / T)^2. (a = acceleration, T = Time to rotate once, r = radius.) <br />
(Note the acceleration only needs to be ~62% of Earth's gravity because we will add Mars' current gravity to this acceleration.)<br />
<br />
So let's say we make an underground hyper loop railway on a circular track on an angle facing inwards (so when it is at speed, the gravity of the railcar plus Mars' gravity faces directly down to the floor of the car).<br />
<br />
If this circular track was 500 meters in diameter, then the car would have to go around the loop every 57 seconds, (say one RPM to round off). The hyper loop railway would have to go 55 meters per second, or 198 km/hour.<br />
<br />
The main reason to make it a hyper-loop is to avoid wear on the wheel's bearings. This speed is doable with Earth trains using today's tech, which have to fight thru Earth's air pressure. (Japan's bullet trains go 320 km/h for example.)<br />
<br />
Assuming the train is 100% as long as the track, and that it is two meters wide, then there is 0.684 square kilometres of area for people to exercise or sleep in. If we make the train 3 stories high, then this area triples.<br />
<br />
If we find that there are no long term ill effects at, say, 0.8 gees of gravity, the speed of the train could be lowered. Alternately the radius could be increased (giving us more living area), without increasing the speed.<br />
<br />
IF, and only if, we find that low gravity is a problem, then people could work 8 hours a day in the low gravity factories or farms. Then live and sleep in an underground habit at Earth gravity. This would also reduce the radiation dose.<br />
<br />
===Eureka Settlement Proposal:===<br />
A [[Gravity|rotating settlement habitat]] is proposed [[Gravity|here]]. The Eureka <ref>https://macroinvent.com/wp-content/uploads/2019/03/Eureka-Mars-Settlement-Concept.pdf</ref>space Settlement was proposed for the [[Mars Colony Design Contest|2019 Mars society design contest.]]<br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Low_gravity&diff=140840Low gravity2024-01-29T01:19:54Z<p>RichardWSmith: /* Increasing Gravity Inside Long Term Mars Habitations */</p>
<hr />
<div>Mars' surface gravity is 3.711 meters / second^2, or about 38% of Earth's gravity.<br />
<br />
There is no medical evidence for the effects on Mars' [[gravity]] on Earth life. Although we could simulate Mars' gravity on the International Space Station using a centrifuge, (with some mice in a cage for example), this experiment has never been done. Plants have been grown successfully in zero gee, so it is likely they would also be viable in 38% gee.<br />
<br />
==Long term medical effects of 38% gravity==<br />
As of 2022, no studies have researched this question. Once we have real data, please update this section.<br />
<br />
==Short term medical effects of 38% gravity==<br />
People with bad knee and hip joints may find Martian gravity to be a boon. In the far future, Mars might be seen as an attractive retirement location for that reason. (Tho Luna with 1/6 of Earth's gravity may be even more attractive.)<br />
<br />
==Martian gravity in fiction==<br />
<br />
<br />
==Increasing Gravity Inside Long Term Mars Habitations==<br />
There is a simple way to increase gravity within a major base on Mars... A centrifuge.<br />
<br />
The formula for centripetal force is:<br />
<br />
a = r(2 PI / T)^2. (a = acceleration, T = Time to rotate once, r = radius.) <br />
(Note the acceleration only needs to be ~62% of Earth's gravity because we will add Mars' current gravity to this acceleration.)<br />
<br />
So let's say we make an underground hyper loop railway on a circular track on an angle facing inwards (so when it is at speed, the gravity of the railcar plus Mars' gravity faces directly down to the floor of the car).<br />
<br />
If this circular track was 500 meters in diameter, then the car would have to go around the loop every 57 seconds, (say one RPM to round off). The hyper loop railway would have to go 55 meters per second, or 198 km/hour.<br />
<br />
The main reason to make it a hyper-loop is to avoid wear on the wheel's bearings. This speed is doable with Earth trains using today's tech, which have to fight thru Earth's air pressure. (Japan's bullet trains go 320 km/h for example.)<br />
<br />
Assuming the train is 100% as long as the track, and that it is two meters wide, then there is 0.684 square kilometres of area for people to exercise or sleep in. If we make the train 3 stories high, then this area triples.<br />
<br />
If we find that there are no long term ill effects at, say, 0.8 gees of gravity, the speed of the train could be lowered. Alternately the radius could be increased (giving us more living area), without increasing the speed.<br />
<br />
IF, and only if, we find that low gravity is a problem, then people could work 8 hours a day in the low gravity factories or farms. Then live and sleep in an underground habit at Earth gravity. This would also reduce the radiation dose.<br />
<br />
===Eureka Settlement Proposal:===<br />
A [[Gravity|rotating settlement habitat]] is proposed [[Gravity|here]]. The Eureka <ref>https://macroinvent.com/wp-content/uploads/2019/03/Eureka-Mars-Settlement-Concept.pdf</ref>space Settlement was proposed for the [[Mars Colony Design Contest|2019 Mars society design contest.]]<br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Low_gravity&diff=140839Low gravity2024-01-29T01:18:30Z<p>RichardWSmith: Made clearer what we are calculating.</p>
<hr />
<div>Mars' surface gravity is 3.711 meters / second^2, or about 38% of Earth's gravity.<br />
<br />
There is no medical evidence for the effects on Mars' [[gravity]] on Earth life. Although we could simulate Mars' gravity on the International Space Station using a centrifuge, (with some mice in a cage for example), this experiment has never been done. Plants have been grown successfully in zero gee, so it is likely they would also be viable in 38% gee.<br />
<br />
==Long term medical effects of 38% gravity==<br />
As of 2022, no studies have researched this question. Once we have real data, please update this section.<br />
<br />
==Short term medical effects of 38% gravity==<br />
People with bad knee and hip joints may find Martian gravity to be a boon. In the far future, Mars might be seen as an attractive retirement location for that reason. (Tho Luna with 1/6 of Earth's gravity may be even more attractive.)<br />
<br />
==Martian gravity in fiction==<br />
<br />
<br />
==Increasing Gravity Inside Long Term Mars Habitations==<br />
There is a simple way to increase gravity within a major base on Mars... A centrifuge.<br />
<br />
The formula for centripetal force is:<br />
<br />
a = r(2 PI / T)^2. (a = acceleration, T = Time to rotate once, r = radius.) <br />
(Note the acceleration only needs to be ~62% of Earth's gravity because we will add Mars' current gravity to this acceleration.)<br />
<br />
So let's say we make an underground hyper loop railway on a circular track on an angle facing inwards (so when it is at speed, the gravity of the railcar plus Mars' gravity faces directly down to the floor of the car).<br />
<br />
If this circular track was 500 meters in diameter, then the car would have to go around the loop every 57 seconds, (say one RPM to round off). The hyper loop railway would have to go 55 meters per second, or 198 km/hour.<br />
<br />
The main reason to make it a hyper-loop is to avoid friction from the Martian dust. This speed is doable with Earth trains using today's tech, which have to fight thru Earth's air pressure. (Japan's bullet trains go 320 km/h for example.)<br />
<br />
Assuming the train is 100% as long as the track, and that it is two meters wide, then there is 0.684 square kilometres of area for people to exercise or sleep in. If we make the train 3 stories high, then this area triples.<br />
<br />
If we find that there are no long term ill effects at, say, 0.8 gees of gravity, the speed of the train could be lowered. Alternately the radius could be increased (giving us more living area), without increasing the speed.<br />
<br />
IF, and only if, we find that low gravity is a problem, then people could work 8 hours a day in the low gravity factories or farms. Then live and sleep in an underground habit at Earth gravity. This would also reduce the radiation dose.<br />
<br />
===Eureka Settlement Proposal:===<br />
A [[Gravity|rotating settlement habitat]] is proposed [[Gravity|here]]. The Eureka <ref>https://macroinvent.com/wp-content/uploads/2019/03/Eureka-Mars-Settlement-Concept.pdf</ref>space Settlement was proposed for the [[Mars Colony Design Contest|2019 Mars society design contest.]]<br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140838Cosmic radiation2024-01-29T01:05:49Z<p>RichardWSmith: /* Point of origin */</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
* [[Solar Cosmic Rays]]. (SCR) These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
* [[Galactic Cosmic Rays]]. (GCR) These are from sources within our galaxy.<br />
* [[Extra Galactic Cosmic Rays]]. (EGCR) These are thought to be generated by active galactic nucleus and quasars.<br />
* [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5% better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140837Cosmic radiation2024-01-29T01:04:18Z<p>RichardWSmith: Discussion of the energies of cosmic rays & mitigation.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
-- [[Solar Cosmic Rays]]. These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]] (CME).<br />
-- [[Galactic Cosmic Rays]]. These are from sources within our galaxy.<br />
-- [[Extra Galactic Cosmic Rays]]. These are thought to be generated by active galactic nucleus and quasars.<br />
-- [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Energies of Cosmic Rays:==<br />
Cosmic rays' energy is measured in Electron Volts (eV). This is the energy of one electron accelerating thru a potential difference of one volt.<br />
<br />
Most solar cosmic rays are from tens of kilo-electron Volts (keV) to several hundred Mega-electron volts (MeV). Rarely (a couple times a decade) during a CME, particles in the tens or hundreds of Giga-electron Volts are generated.<br />
<br />
Galactic cosmic rays can have arbitrarily low energies, but have maximum energies from 10 GeV to hundreds of Tera-electron volts.<br />
<br />
Extra galactic cosmic rays have energies of giga or tera electron volts (like 'local' CR) but can have Peta-electron volts (PeV) or even up to 50 exa-electron volts (EeV).<br />
<br />
Current theory says that 50 EeV particles are the highest we should detect, but occasionally (a handful of times a decade) we detect particles with more energy than this. TWO particles have been detected with over 200 EeV.<br />
<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
<br />
===Thinking about comic rays:===<br />
Solar cosmic rays are relatively easy to shield against, with the exception of the rare, very high particles from the most powerful of CME. These are 10 thousand to a million times more powerful than normal. For simplicity sake, these once in a decade events can be lumped in with Galactic cosmic rays, with the understanding that if they occur during local night, there is complete protection against them by the mass of Mars itself.<br />
<br />
Galactic cosmic rays blend in (at low energies) with solar cosmic rays. The low energy ones we will basically ignore. (If we are shielding against solar CR, we will shield against these.) However, these lower energy Galactic cosmic rays have an interesting property: the sun's magnetosphere gives us partial protection, so when the sun is most active during a [[Solar Maximum]], we end up getting fewer of these low energy cosmic rays then when the sun is less active. Thus for people in space, the total cosmic ray count is LOWER when he sun is active! The high energy galactic cosmic rays move so fast that they punch thru magnetic fields. Thus on Earth, we get GCR at all times of the year, near the magnetic poles and at the equator, regardless of the sun's activity. The only protection is to go deep, far underground. On Earth, we accept the dose of these rays, year in and year out. There is no protecting against them for normal people, so we ignore them.<br />
<br />
The Extra-galactic cosmic rays and the OMG particles likewise defeat any shielding and we just have to live with them.<br />
<br />
<br />
Now the Earth's thicker atmosphere is 62.5% better at blocking out the high energy cosmic rays. (Because the mass column of Mars' atmosphere is 1.6% of what it is on Earth.) This means that Mars will have a higher radiation dose from GCR. Realistically, Martian colonists will accept a higher radiation dose, tho this can be mitigated by having a meter of water, or a half meter of soil between the people and the sky.<br />
<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140836Cosmic radiation2024-01-29T00:28:43Z<p>RichardWSmith: /* Point of origin */ Discussed the 4 different types of cosmic rays.</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
Cosmic Rays are divided into 4 general classes:<br />
-- [[Solar Cosmic Rays]]. These are not the normal solar wind, but are rare, high-energy particles from [[Coronal Mass Ejections]].<br />
-- [[Galactic Cosmic Rays]]. These are from sources within our galaxy.<br />
-- [[Extra Galactic Cosmic Rays]]. These are thought to be generated by active galactic nucleus and quasars.<br />
-- [[Extreme Energy Cosmic Rays]] (Sometimes known as the OMG particles.) We do not have any good explanation of how these are created.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_radiation&diff=140835Cosmic radiation2024-01-29T00:18:59Z<p>RichardWSmith: Added that some people think that cosmic rays are caused by kilo nova (colliding white dwarfs or neutron stars).</p>
<hr />
<div>'''Cosmic radiation''' (also known as cosmic rays) is created in deep space by strong electric and magnetic processes, stripping atoms down to the core and accelerating them to high velocities. Those high energetic particles reach the surface of [[Mars]] due to the very thin [[atmosphere]]. Like all other ionizing [[radiation]] it causes damage to material and health.<br />
<br />
==Point of origin==<br />
Cosmic radiation strikes bodies in the solar system from all directions, as they permeate the galaxy. They are made of the same particles in the same proportion as [[solar wind|those originating from the sun]]; and are considered part of space weather.<ref name="SME">W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell eds. ''Space mission engineering: The new SMAD''. 2011. pp. 127-137. ISBN 978-1-881883-15-9</ref>. <br />
How they are created is debated, but being accelerating by matter falling into a black hole, from colliding stellar remnants (white dwarfs or neutron stars), or being created by shock waves from supernova are three common explanations of their origins.<br />
<br />
==Mitigating Cosmic Rays:==<br />
Cosmic rays are blocked by planets, so people on a planet (or in close orbit around one), receive half the cosmic rays that you would in deep space. (The horizon blocks out half the sky, a bit more if you are in a valley.) Cosmic rays (and their [[Secondary radiation]]) will penetrate fairly deep thru earth and rock, so only by being deep underground can they be totally eliminated. Experiments on Earth which wish to avoid cosmic rays are done in mines more than 2,000 meters below ground.<br />
<br />
That said, people receive cosmic rays everywhere on Earth. People living at high altitudes (which get a higher dose than those living at sea level) show no higher signs of health problems. So trying to eliminate all cosmic rays is impossible and futile. But habitats with a meter of water (or a half meter of soil) between people and the sky would reduce this radiation to levels approaching high altitude regions on Earth. See [[Radiation shielding]] for more details.<br />
<br />
Note that small electromagnetic fields do not protect against cosmic rays (tho they do help with low and medium energy solar particles). If people were somehow to give Mars a magnetosphere, (say with superconducting current around the equator), it would help against low energy cosmic rays but not against higher energy ones. (Cosmic rays strike everywhere on Earth, not just near the magnetic poles.)<br />
<br />
The only protection from cosmic rays is lots of mass, either a thick atmosphere, or a meter or so of soil or water. Even then, the protection is not perfect. (Everyone on Earth is bathed by cosmic rays, despite our thick atmosphere and Earth's magnetic field.) Habitats in a [[Lava tube]] have been proposed as an inexpensive way to give many meters of protection from this radiation.<br />
<br />
==Acute effects on equipment==<br />
A single strike by a cosmic ray can cause three types of error in electronic equipment<ref name="SME" />:<br />
<br />
*[[Single-event upset]]<br />
*[[Single-event latchup]]<br />
*[[Single-event burnout]]<br />
<br />
Note that modern integrated circuits (with millions of tiny transistors), are more likely to be effected by cosmic rays than more primitive integrated circuits (with a few tens of thousand large transistors). Native Mars electronic firms may chose to optimize their products for a higher radiation environment. This is one area where lower tech Martian industries may have a local advantage over Earth's. See this report about data faults caused by radiation (all sorts of radiation, not just cosmic rays). <ref>https://llis.nasa.gov/lesson/824</ref><br />
<br />
==Chronic effects on equipment==<br />
None have been noticed after decades of work on the ISS (International Space Station).<br />
<br />
==Acute effects on life==<br />
None have been noticed on the ISS. Note that cosmic rays are a low level of back ground radiation, so they are not an 'acute' radiation dose. (Sudden bursts of high radiation are much more dangerous than low levels over a long time.) Six astronauts or cosmonauts who have spent a few long missions on the ISS or Mir space stations have received radiation doses greater (in some cases double), than the radiation dose from a 2.5 year long Mars mission. None of them have shown any health issues from radiation.<br />
<br />
==Chronic effects on life==<br />
Radiation effects on life have been studied for over 7 decades, cosmic rays (and the [[Secondary radiation]] they produce) are well understood. The chronic effects on life are based on what the long term level of radiation is. The average radiation level on Earth is 2.4 mSv (240 mrem) per year (note this includes ALL radiation, not just cosmic rays). However, the Iranian city of Ramsar has natural levels of radiation 30 to 50 times higher than average on Earth, and show no statistical increase of cancers or early death than elsewhere. <ref>https://en.wikipedia.org/wiki/Background_radiation</ref> This suggests that total radiation levels of up to 100 mSv per year, would be a reasonable target for Martian habitats. This value is 5 times higher than the (very conservative) levels of radiation allowed for workers in nuclear plants. <ref>https://www.admnucleartechnologies.com.au/blog/what-safe-level-radiation-exposure</ref><br />
<br />
Since [[Habitat|habitats]] have been designed, with a meter of dirt as radiation protection, which approach this value, a well constructed habitat would be unlikely to have a noticeable chronic effect on life. Poorly constructed habitats with little or no thought given to radiation protection would be expected to have a statistically higher chance of cancer (the most common form of disease caused by radiation).<br />
<br />
==References==<br />
<references /><br />
<br />
[[Category:Radiation Protection]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Hardened_electronics&diff=140834Hardened electronics2024-01-29T00:14:39Z<p>RichardWSmith: Pointed out that larger computer chips are more resistant to radiation.</p>
<hr />
<div>[[Electronics]] in transit to, and on the surface of [[Mars]] are constantly bombarded by [[radiation]]. '''Hardened electronics''' are designed to resist the effects of this radiation to some degree, extending the [[wear lifespan]] to several months or even a couple years. Note that computer chips have grown LESS radiation resistant as they have grown smaller. As transistors have gone from trillions of atoms, to millions, to thousands of atoms, the chance of a cosmic ray 'flipping a bit' (also known as a one off event) becomes higher. It is likely that lower tech, larger chips build in early Mars industries, will be inherently more radiation resistant.<br />
<br />
==Physical Hardening==<br />
Physical [[radiation shielding|shielding]], such as [[heavy metals]] or a [[Faraday Cage]] can block many types of radiation before it affects the electronics. Depending on the shield strength, the incoming radiation is reduced to a lower value.<br />
<br />
==Design Hardening==<br />
Electronics can be designed to resist radiation, to a certain degree. The size of semiconductor structures, for example, has an effect. Fine structures are more prone to radiation damage than chunky structures.<br />
<br />
==Hardened Programming==<br />
[[Fail-safe|Redundancy]], sanity checks, and dead man switches can ensure reliability and notify operators of errors. The system is able to continue working even if parts are damaged. The faulty parts are automatically recognized and switched off.<br />
<br />
==External Links==<br />
<br />
[http://ti.arc.nasa.gov/tech/rse/publications/papers/AIAA05/rhs.pdf Expecting the Unexpected - Radiation Hardened Software (NASA)]<br />
<br />
{{stub}}<br />
[[category:Instruments]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Cosmic_rays&diff=140833Cosmic rays2024-01-29T00:04:21Z<p>RichardWSmith: Changed wording to make more scientifically correct.</p>
<hr />
<div>Cosmic rays (also known as cosmic radiation) are high energy particles that are part of the background radiation in space. Most cosmic rays are absorbed in the Earth's atmosphere and do not reach the planet's surface. However, a cosmic ray that hits an air molecule shatters into a shower of secondary radiation traveling within 1 degree of the original direction, and much of this secondary radiation does reach the Earth's surface. About 0.390 milliSieverts of radiation per year come from cosmic rays on Earth. (100 milliSieverts of radiation in a year is the smallest amount known to cause an increase of cancer; 400 milliSieverts of radiation in a short time, (under several days), might cause symptoms of radiation poisoning.) In orbit astronauts take ~150 mSV of radiation (but this includes radiation from the sun. (Currently trying to find solar and cosmic radiation broken out from each other.) <br />
<br />
Note that the lowest energy cosmic rays have similar energies to the highest energy particles from the sun, so the two blend into each other. Strategies to mitigate the strongest solar events will help with the weakest cosmic rays. <br />
<br />
Cosmic rays have detrimental effects on human health<ref>https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays</ref>. <br />
<br />
Since cosmic rays come from every direction, being on a planet will automatically halve your cosmic ray dose compared to deep space, since half of the sky is blocked by the planet beneath your feet. <br />
<br />
On Mars, about 1.6% of cosmic rays are absorbed by the thin atmosphere, (pretty good considering the air has 0.6% as much pressure as Earth). Therefore [[radiation shielding]] is required for the habitats. <br />
==Composition==<br />
Cosmic radiation comprises 85% protons, 14% alpha particles, and 1% heavy ions.<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref><br />
<br />
==Energy==<br />
[[File:GCR spectra.png|alt=|frame|Energy distribution of cosmic radiation, as measured during the 1977 solar minimum.<ref>Kim MY, Thibeault SA, Simonsen LC, Wilson JW. (1998). Comparison of Martian Meteorites and Martian Regolith as Shield Materials for Galactic Cosmic Rays. NASA TP-1998-208724. <nowiki>http://hdl.handle.net/2060/19980237030</nowiki></ref>|none]]<br />
<br />
== Variation because of the solar cycle ==<br />
The sun has a ~11 year solar cycle. At the peak of the cycle the magnetic field is stronger, there are more sunspots, and the sun is slightly hotter. There are more solar flares (coronal mass ejections). At the low point of the cycle the sun is cooler, and less magnetically active. At the peak of the cycle the more powerful magnetic field will deflect the weaker cosmic rays away from the ecliptic and redirect them towards the poles of the sun. Note that the higher power cosmic rays will punch thru regardless, so even when the solar magnetic field is at its strongest, we still get many cosmic rays. <br />
<br />
This change in radiation is significant, the radiation increase between the very lowest and strongest solar cycles is ~75% (tho ~34% is more typical).<ref>https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002428<br />
<br />
</ref> This suggests that we can profitably trade off lower cosmic ray doses for higher solar radiation doses by launching missions during solar maximum.<br />
<br />
The sun for the last few decades has been unusually cool, so the the cosmic ray dose is relatively higher than, say, a century ago.<br />
<br />
== Albedo neutrons ==<br />
Cosmic rays when they hit Mars' soil will set off secondary radiation including free neutrons (called albedo neutrons). This is a radiation source which is very low on Earth. Water, plastics, or substances such as Lithium Hydroxide would help absorb these neutrons for long term settlements. <ref>https://www.tandfonline.com/doi/abs/10.1179/1743284715Y.0000000105?journalCode=ymst20</ref><br />
<br />
==References==<br />
[[Category:Medicine]]<br />
[[Category:Radiation Protection]]<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Zhurong&diff=139956Zhurong2023-02-28T00:21:50Z<p>RichardWSmith: /* Technical Innovations */ grammar</p>
<hr />
<div>Zhurong is a six-wheeled rover built by China. It landed on Mars in the area called Utopia Planitia on May 14, 2021. Zhurong is about the size of NASA's twin Mars rovers Spirit and Opportunity. It has six scientific instruments, including two panoramic cameras, a ground-penetrating radar and a magnetic field detector. Like America's Curiosity and Perseverance Martian rovers, Zhurong has a laser to zap rocks and thereby study their compositions.<ref>https://www.space.com/china-mars-rover-landing-success-tianwen-1-zhurong</ref><br />
<br />
==Summary==<br />
<gallery class="center" widths="380px" heights="360px"><br />
<br />
File:ESP 070377 2050chinawide.jpg|Wide view of landscape near where Zhurong is exploring, as seen by HiRISE Scale bar at the top is 500 meters long.<br />
<br />
File:ESP 070377 2050china.jpg|Region near China's Rover, as seen by HiRISE<br />
<br />
File:ZhurongChina.jpg|Zhurong, as seen by HiRISE. It's tracks are indicated with blue arrow.<br />
<br />
</gallery><br />
<br />
Research published in May, 2022 described chemical evidence for water discovered by the Zhurong Rover. Hydrated sulfate/silica materials were identified on the Amazonian-age terrain at the landing site. These hydrated minerals were found in bright-toned rocks. Authors of the research interpreted these minerals to be from a "duricrust." The duricrust was formed either by groundwater rising or subsurface ice melting. This duricrust was created just under the surface,and then was uncovered by erosion. <br />
<br />
Finding these minerals here suggests that water may have been present at later times then thought. Perhaps liquid water appeared after impacts or from hot magma under the surface. We know there is much ice under the surface and any heat might melt it, and then the water could carry dissolved minerals around. The minerals could then be deposited when water evaporated.<ref>https://www.science.org/doi/10.1126/sciadv.abn8555</ref> <ref>Liu, Y., et al. 2022. Zhurong reveals recent aqueous activities in Utopia Planitia, Mars. Science Advances. VOL. 8, NO. 19</ref><br />
<br />
==Technical Innovations==<br />
Under two circular windows are ten containers which hold N-undecane (a chemical used as a sex pheromone by cockroaches and moths), which will melt in the Martian day time, and freeze at night. This chemical has a high heat of fusion, so it will release a fair amount of heat just when the Martian night is getting coldest. It was hoped that this would prolong the life of the Rover by keeping batteries and key electronics warmer at night.<ref>https://twitter.com/CNDeepSpace/status/1478755108074627074</ref><br />
<br />
==End of Mission==<br />
Solar cells have a short life on Mars (due to dust build up), and as of late February, 2023, the Zhurong rover has been immobile for months. It should have woken up last month. Zhurong had anti dust coatings on its solar cells, but moving dust on Mars builds up static charges which cause them to stick to surfaces strongly. China has not announced the end of the mission, so perhaps the engineers hope that the rover may still recover.<ref>https://www.nature.com/articles/d41586-023-00111-3</ref><br />
== References ==<br />
<br />
{{reflist|colwidth=30em}}<br />
<br />
<br />
=See also=<br />
<br />
*[[Mars Perseverance Rover]]<br />
<br />
*[[Tianwen-1]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Zhurong&diff=139955Zhurong2023-02-28T00:20:28Z<p>RichardWSmith: Is Zhurong dead? Added section on technical innovations.</p>
<hr />
<div>Zhurong is a six-wheeled rover built by China. It landed on Mars in the area called Utopia Planitia on May 14, 2021. Zhurong is about the size of NASA's twin Mars rovers Spirit and Opportunity. It has six scientific instruments, including two panoramic cameras, a ground-penetrating radar and a magnetic field detector. Like America's Curiosity and Perseverance Martian rovers, Zhurong has a laser to zap rocks and thereby study their compositions.<ref>https://www.space.com/china-mars-rover-landing-success-tianwen-1-zhurong</ref><br />
<br />
==Summary==<br />
<gallery class="center" widths="380px" heights="360px"><br />
<br />
File:ESP 070377 2050chinawide.jpg|Wide view of landscape near where Zhurong is exploring, as seen by HiRISE Scale bar at the top is 500 meters long.<br />
<br />
File:ESP 070377 2050china.jpg|Region near China's Rover, as seen by HiRISE<br />
<br />
File:ZhurongChina.jpg|Zhurong, as seen by HiRISE. It's tracks are indicated with blue arrow.<br />
<br />
</gallery><br />
<br />
Research published in May, 2022 described chemical evidence for water discovered by the Zhurong Rover. Hydrated sulfate/silica materials were identified on the Amazonian-age terrain at the landing site. These hydrated minerals were found in bright-toned rocks. Authors of the research interpreted these minerals to be from a "duricrust." The duricrust was formed either by groundwater rising or subsurface ice melting. This duricrust was created just under the surface,and then was uncovered by erosion. <br />
<br />
Finding these minerals here suggests that water may have been present at later times then thought. Perhaps liquid water appeared after impacts or from hot magma under the surface. We know there is much ice under the surface and any heat might melt it, and then the water could carry dissolved minerals around. The minerals could then be deposited when water evaporated.<ref>https://www.science.org/doi/10.1126/sciadv.abn8555</ref> <ref>Liu, Y., et al. 2022. Zhurong reveals recent aqueous activities in Utopia Planitia, Mars. Science Advances. VOL. 8, NO. 19</ref><br />
<br />
==Technical Innovations==<br />
Under two circular windows are ten containers which hold N-undecane (a chemical used as sex pheromone by cockroaches and moths), which will melt in the Martian day time, and freeze at night. This chemical has a high heat of fusion, so it will release a fair amount of heat just when the Martian night is getting coldest. It was hoped that this would prolong the life of the Rover by keeping batteries and key electronics warmer at night.<ref>https://twitter.com/CNDeepSpace/status/1478755108074627074</ref><br />
<br />
==End of Mission==<br />
Solar cells have a short life on Mars (due to dust build up), and as of late February, 2023, the Zhurong rover has been immobile for months. It should have woken up last month. Zhurong had anti dust coatings on its solar cells, but moving dust on Mars builds up static charges which cause them to stick to surfaces strongly. China has not announced the end of the mission, so perhaps the engineers hope that the rover may still recover.<ref>https://www.nature.com/articles/d41586-023-00111-3</ref><br />
== References ==<br />
<br />
{{reflist|colwidth=30em}}<br />
<br />
<br />
=See also=<br />
<br />
*[[Mars Perseverance Rover]]<br />
<br />
*[[Tianwen-1]]</div>RichardWSmithhttp://marspedia.org/index.php?title=Nuclear_thermal_propulsion&diff=139911Nuclear thermal propulsion2023-01-24T11:36:09Z<p>RichardWSmith: removed redundant reference (listed again below.)</p>
<hr />
<div>[[Category:Propulsion]]<br />
Nuclear Thermal Propulsion (NTP) uses a nuclear reactor to heat [[propellant]] directly and exhaust it through a rocket nozzle. The nuclear reactor core is the hottest element in the engine and limits the effectiveness of the drive. (Tho nuclear reactors could be made to run hotter, removing waste heat is a great concern to prevent the reactor from melting. Radiating heat in space is more difficult than on a planet since there is no mass to dump heat into via convection.)<br />
<br />
Liquid hydrogen is usually used as the propellant as it has a higher velocity for the same input power, and therefore produces a faster final velocity according to the [[Propulsion|rocket equation]]. An animated illustration of nuclear thermal rockets can be found at <ref>https://www.youtube.com/watch?v=3aBOhC1c6m8</ref>.<br />
<br />
Nuclear thermal engines allow for shorter transit times and/or lower propellant requirements than chemical engines. They are usually planed for orbital operations only, and are in completion with alternative technologies such as [[Nuclear Electric Propulsion]] (NEP) and [[Solar Electric Propulsion]] (SEP).<br />
<br />
In the late 1960's NASA explored nuclear propulsion with the NERVA program. It was expected that such nuclear rockets could achieve efficiencies of 900 seconds ISP. (This is twice the efficiency of chemical rockets where efficiently engineered hydrogen-oxygen engines are around 450 seconds ISP.)<br />
<br />
However, a little know technology, the wave rotor, can be used to further compress the hot gas from a nuclear rocket before it enters the rocket nozzle. This can boost the ISP to 1,400 to 2,000 seconds. If such a rocket with an ISP or 1,800 seconds could be created, missions to Mars would need 1/2 the reaction mass of a NERVA rocket, or 1/4 the reaction mass of a chemical rocket. This would allow much more payload to be sent to Mars, and increase the safety, and efficiency of such missions.<ref>https://www.egr.msu.edu/mueller/NMReferences/HirceagaIancuMueller_2005Timisoara_WaveRotorsTechnologyAndApplications.pdf</ref><ref>https://www.nextbigfuture.com/2023/01/nuclear-wave-rotor-propulsion-could-get-ten-times-chemical-rocket-speeds.html</ref><br />
<br />
Wave Rotor Nuclear Thermal Propulsion (WRNTP) is an extremely interesting technology, but as of 2023, no working motors have been demonstrated.<br />
<br />
__NOTOC__<br />
==History of nuclear thermal propulsion==<br />
<br />
===American===<br />
Nerva<ref>Nerva on Wikipedia: https://en.wikipedia.org/wiki/NERVA</ref> <br />
{| class="wikitable"<br />
!Propellant<br />
|Liquid hydrogen<br />
|-<br />
! colspan="2" |Performance<br />
|-<br />
!Thrust (vac.)<br />
|246,663 N (55,452 lb<sub>f</sub>) <br />
|-<br />
!Chamber pressure<br />
|3,861 kPa (560.0 psi)<br />
|-<br />
!''I''<sub>sp</sub> (vac.)<br />
|841 seconds (8.25 km/s)<br />
|-<br />
!''I''<sub>sp</sub> (SL)<br />
|710 seconds (7.0 km/s)<br />
|-<br />
!Burn time<br />
|1,680 seconds<br />
|-<br />
!Thrust to weigh ratio<br />
!1.36<br />
|-<br />
!Restarts<br />
|24<br />
|-<br />
! colspan="2" |Dimensions<br />
|-<br />
!Length<br />
|6.9 meters (23 ft)<br />
|-<br />
!Diameter<br />
|2.59 meters (8 ft 6 in)<br />
|-<br />
!Dry weight<br />
|18,144 kilograms (40,001 lb)<br />
|}<br />
<br />
*<br />
<br />
*<br />
<br />
===Russian===<br />
<br />
==Analysis of use==<br />
<br />
===Advantages===<br />
<br />
*Higher ISP than chemical<br />
*Higher power energy source<br />
*Shorter travel time<br />
*Oberth effect<br />
*Self cooling<br />
<br />
===Disadvantages===<br />
<br />
*Cost<br />
*Cost of development<br />
*Risk of accident<br />
*Lower ISP than electric<br />
*Low public trust<br />
*Thrust to weight ratio close to 1 (cannot take off from Earth with a significant payload)<br />
<br />
===Types===<br />
<br />
*Solid core<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960001947.pdf</ref><br />
*Gas core<ref>https://deepblue.lib.umich.edu/bitstream/handle/2027.42/87734/585_1.pdf</ref><br />
*Nuclear light bulb, open and closed<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690014077.pdf</ref><br />
*Wave Rotor NTP<ref>https://www.nasa.gov/directorates/spacetech/niac/2023/New_Class_of_Bimodal/</ref><br />
*Nuclear salt water rockets<ref>http://www.path-2.narod.ru/design/base_e/nswr.pdf</ref><br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Nuclear_thermal_propulsion&diff=139910Nuclear thermal propulsion2023-01-24T11:35:19Z<p>RichardWSmith: Added Wave Rotor to list.</p>
<hr />
<div>[[Category:Propulsion]]<br />
Nuclear Thermal Propulsion (NTP) uses a nuclear reactor to heat [[propellant]] directly and exhaust it through a rocket nozzle. The nuclear reactor core is the hottest element in the engine and limits the effectiveness of the drive. (Tho nuclear reactors could be made to run hotter, removing waste heat is a great concern to prevent the reactor from melting. Radiating heat in space is more difficult than on a planet since there is no mass to dump heat into via convection.)<br />
<br />
Liquid hydrogen is usually used as the propellant as it has a higher velocity for the same input power, and therefore produces a faster final velocity according to the [[Propulsion|rocket equation]]. An animated illustration of nuclear thermal rockets can be found at <ref>https://www.youtube.com/watch?v=3aBOhC1c6m8</ref>.<br />
<br />
Nuclear thermal engines allow for shorter transit times and/or lower propellant requirements than chemical engines. They are usually planed for orbital operations only, and are in completion with alternative technologies such as [[Nuclear Electric Propulsion]] (NEP) and [[Solar Electric Propulsion]] (SEP).<br />
<br />
In the late 1960's NASA explored nuclear propulsion with the NERVA program. It was expected that such nuclear rockets could achieve efficiencies of 900 seconds ISP. (This is twice the efficiency of chemical rockets where efficiently engineered hydrogen-oxygen engines are around 450 seconds ISP.)<br />
<br />
However, a little know technology, the wave rotor, can be used to further compress the hot gas from a nuclear rocket before it enters the rocket nozzle. This can boost the ISP to 1,400 to 2,000 seconds. If such a rocket with an ISP or 1,800 seconds could be created, missions to Mars would need 1/2 the reaction mass of a NERVA rocket, or 1/4 the reaction mass of a chemical rocket. This would allow much more payload to be sent to Mars, and increase the safety, and efficiency of such missions.<ref>https://www.egr.msu.edu/mueller/NMReferences/HirceagaIancuMueller_2005Timisoara_WaveRotorsTechnologyAndApplications.pdf</ref><ref>https://www.nextbigfuture.com/2023/01/nuclear-wave-rotor-propulsion-could-get-ten-times-chemical-rocket-speeds.html</ref><ref>https://www.nasa.gov/directorates/spacetech/niac/2023/New_Class_of_Bimodal/</ref><br />
<br />
Wave Rotor Nuclear Thermal Propulsion (WRNTP) is an extremely interesting technology, but as of 2023, no working motors have been demonstrated.<br />
<br />
__NOTOC__<br />
==History of nuclear thermal propulsion==<br />
<br />
===American===<br />
Nerva<ref>Nerva on Wikipedia: https://en.wikipedia.org/wiki/NERVA</ref> <br />
{| class="wikitable"<br />
!Propellant<br />
|Liquid hydrogen<br />
|-<br />
! colspan="2" |Performance<br />
|-<br />
!Thrust (vac.)<br />
|246,663 N (55,452 lb<sub>f</sub>) <br />
|-<br />
!Chamber pressure<br />
|3,861 kPa (560.0 psi)<br />
|-<br />
!''I''<sub>sp</sub> (vac.)<br />
|841 seconds (8.25 km/s)<br />
|-<br />
!''I''<sub>sp</sub> (SL)<br />
|710 seconds (7.0 km/s)<br />
|-<br />
!Burn time<br />
|1,680 seconds<br />
|-<br />
!Thrust to weigh ratio<br />
!1.36<br />
|-<br />
!Restarts<br />
|24<br />
|-<br />
! colspan="2" |Dimensions<br />
|-<br />
!Length<br />
|6.9 meters (23 ft)<br />
|-<br />
!Diameter<br />
|2.59 meters (8 ft 6 in)<br />
|-<br />
!Dry weight<br />
|18,144 kilograms (40,001 lb)<br />
|}<br />
<br />
*<br />
<br />
*<br />
<br />
===Russian===<br />
<br />
==Analysis of use==<br />
<br />
===Advantages===<br />
<br />
*Higher ISP than chemical<br />
*Higher power energy source<br />
*Shorter travel time<br />
*Oberth effect<br />
*Self cooling<br />
<br />
===Disadvantages===<br />
<br />
*Cost<br />
*Cost of development<br />
*Risk of accident<br />
*Lower ISP than electric<br />
*Low public trust<br />
*Thrust to weight ratio close to 1 (cannot take off from Earth with a significant payload)<br />
<br />
===Types===<br />
<br />
*Solid core<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960001947.pdf</ref><br />
*Gas core<ref>https://deepblue.lib.umich.edu/bitstream/handle/2027.42/87734/585_1.pdf</ref><br />
*Nuclear light bulb, open and closed<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690014077.pdf</ref><br />
*Wave Rotor NTP<ref>https://www.nasa.gov/directorates/spacetech/niac/2023/New_Class_of_Bimodal/</ref><br />
*Nuclear salt water rockets<ref>http://www.path-2.narod.ru/design/base_e/nswr.pdf</ref><br />
<br />
==References==<br />
<references /></div>RichardWSmithhttp://marspedia.org/index.php?title=Nuclear_thermal_propulsion&diff=139909Nuclear thermal propulsion2023-01-24T11:32:36Z<p>RichardWSmith: </p>
<hr />
<div>[[Category:Propulsion]]<br />
Nuclear Thermal Propulsion (NTP) uses a nuclear reactor to heat [[propellant]] directly and exhaust it through a rocket nozzle. The nuclear reactor core is the hottest element in the engine and limits the effectiveness of the drive. (Tho nuclear reactors could be made to run hotter, removing waste heat is a great concern to prevent the reactor from melting. Radiating heat in space is more difficult than on a planet since there is no mass to dump heat into via convection.)<br />
<br />
Liquid hydrogen is usually used as the propellant as it has a higher velocity for the same input power, and therefore produces a faster final velocity according to the [[Propulsion|rocket equation]]. An animated illustration of nuclear thermal rockets can be found at <ref>https://www.youtube.com/watch?v=3aBOhC1c6m8</ref>.<br />
<br />
Nuclear thermal engines allow for shorter transit times and/or lower propellant requirements than chemical engines. They are usually planed for orbital operations only, and are in completion with alternative technologies such as [[Nuclear Electric Propulsion]] (NEP) and [[Solar Electric Propulsion]] (SEP).<br />
<br />
In the late 1960's NASA explored nuclear propulsion with the NERVA program. It was expected that such nuclear rockets could achieve efficiencies of 900 seconds ISP. (This is twice the efficiency of chemical rockets where efficiently engineered hydrogen-oxygen engines are around 450 seconds ISP.)<br />
<br />
However, a little know technology, the wave rotor, can be used to further compress the hot gas from a nuclear rocket before it enters the rocket nozzle. This can boost the ISP to 1,400 to 2,000 seconds. If such a rocket with an ISP or 1,800 seconds could be created, missions to Mars would need 1/2 the reaction mass of a NERVA rocket, or 1/4 the reaction mass of a chemical rocket. This would allow much more payload to be sent to Mars, and increase the safety, and efficiency of such missions.<ref>https://www.egr.msu.edu/mueller/NMReferences/HirceagaIancuMueller_2005Timisoara_WaveRotorsTechnologyAndApplications.pdf</ref><ref>https://www.nextbigfuture.com/2023/01/nuclear-wave-rotor-propulsion-could-get-ten-times-chemical-rocket-speeds.html</ref><ref>https://www.nasa.gov/directorates/spacetech/niac/2023/New_Class_of_Bimodal/</ref><br />
<br />
Wave Rotor Nuclear Thermal Propulsion (WRNTP) is an extremely interesting technology, but as of 2023, no working motors have been demonstrated.<br />
<br />
__NOTOC__<br />
==History of nuclear thermal propulsion==<br />
<br />
===American===<br />
Nerva<ref>Nerva on Wikipedia: https://en.wikipedia.org/wiki/NERVA</ref> <br />
{| class="wikitable"<br />
!Propellant<br />
|Liquid hydrogen<br />
|-<br />
! colspan="2" |Performance<br />
|-<br />
!Thrust (vac.)<br />
|246,663 N (55,452 lb<sub>f</sub>) <br />
|-<br />
!Chamber pressure<br />
|3,861 kPa (560.0 psi)<br />
|-<br />
!''I''<sub>sp</sub> (vac.)<br />
|841 seconds (8.25 km/s)<br />
|-<br />
!''I''<sub>sp</sub> (SL)<br />
|710 seconds (7.0 km/s)<br />
|-<br />
!Burn time<br />
|1,680 seconds<br />
|-<br />
!Thrust to weigh ratio<br />
!1.36<br />
|-<br />
!Restarts<br />
|24<br />
|-<br />
! colspan="2" |Dimensions<br />
|-<br />
!Length<br />
|6.9 meters (23 ft)<br />
|-<br />
!Diameter<br />
|2.59 meters (8 ft 6 in)<br />
|-<br />
!Dry weight<br />
|18,144 kilograms (40,001 lb)<br />
|}<br />
<br />
*<br />
<br />
*<br />
<br />
===Russian===<br />
<br />
==Analysis of use==<br />
<br />
===Advantages===<br />
<br />
*Higher ISP than chemical<br />
*Higher power energy source<br />
*Shorter travel time<br />
*Oberth effect<br />
*Self cooling<br />
<br />
===Disadvantages===<br />
<br />
*Cost<br />
*Cost of development<br />
*Risk of accident<br />
*Lower ISP than electric<br />
*Low public trust<br />
*Thrust to weight ratio close to 1 (cannot take off from Earth with a significant payload)<br />
<br />
===Types===<br />
<br />
*Solid core<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960001947.pdf</ref><br />
*Gas core<ref>https://deepblue.lib.umich.edu/bitstream/handle/2027.42/87734/585_1.pdf</ref><br />
*Nuclear light bulb, open and closed<ref>https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690014077.pdf</ref><br />
*Nuclear salt water rockets<ref>http://www.path-2.narod.ru/design/base_e/nswr.pdf</ref><br />
<br />
==References==<br />
<references /></div>RichardWSmith