Marspedia - User contributions [en]

Mars Express

2012-01-19T03:32:34Z

109.230.216.60: /* Instrumentation */

[[Image:Mars Express X orbit 2a-new.jpg|thumb|right|300px|Artists impression of the Mars Express orbiter]]

'''Mars Express''' was launched on June 2, 2003 from [[Baikonur Cosmodrome]] (Kazakhstan) on a [[Soyuz-Fregat rocket]] to search for water and the possibility of Martian life. Consisting of a low-cost orbiter and lander, ''Mars Express'' is a [[European Space Agency]] (ESA) mission to the Red Planet involving a consortium of countries (primarily France, Germany, Great Britain, Ireland, Italy, Japan, the Netherlands, Norway, Russia, Sweden, Spain, and the United States). In February 2007, ''Mars Express'' was granted a second mission extension until May 2009.

==Mission Overview==
[[Image:Mars express logo.jpg|thumb|left|200px|Official [[ESA]] Mars Express mission logo.]]
''Mars Express'' was a two-component mission consisting of the ''Mars Express Orbiter'' and [[Beagle 2]] lander. Unfortunately, the ''Beagle 2'' lander failed on entry into the Martian atmosphere and was lost on Christmas Day, 2003. The crash site of ''Beagle 2'' was later imaged by [[NASA]]'s [[Mars Global Surveyor]] in a crater near the planned landing site of the equatorial region known as [[Isidis Planitia]]. Despite this early loss, the ''Mars Express orbiter'' continues on its mission to explore the Martian surface.

Mars Express will be providing support for the [[NASA]] [[Phoenix]] lander when it arrives on Mars in mid-2008.

Great stuff, you hpeeld me out so much!

== Scientific Discoveries ==

Mars Express has made several important discoveries during its mission:

* Detection of [[water]] in the southern polar icecap using OMEGA (2004)
* Detection of [[methane]] & [[ammonia]] in the Martian atmosphere using PFS (2004)
* Location of an area of water ice near the north pole using HRSC (2005)
* Mapping the [[water|location and thickness of water ice]] in the south pole with the MARSIS instrument (2007)

It has also carried out a wide variety of other important observations which have increased understanding of the Martian atmosphere and geology.

== External links ==
* [http://www.esa.int/SPECIALS/Mars_Express/index.html ESA's Mars Express pages]
* [http://www.esa.int/esa-mmg/mmg.pl?mission=Mars+Express Recent Mars Express images]
* [http://marsprogram.jpl.nasa.gov/express/ NASA's Mars Express pages]
* [http://en.wikipedia.org/wiki/Mars_Express Wikipedia page on Mars Express]

[[category:Orbiters]]

Reverse Water-Gas Shift Reaction

2012-01-19T03:20:59Z

109.230.216.60: /* Production of carbon monoxide */

The '''Reverse Water-Gas Shift Reaction''' (RWGS reaction) was discovered in the 19th century as a method of producing [[water]] from [[carbon dioxide]] and [[hydrogen]], with [[carbon monoxide]] as a side product. In the context of [[manned mission|human missions]] to [[Mars]], it has been proposed as a complement to the Sabatier/water electrolysis (SE) process to produce [[methane]] and [[oxygen]] from hydrogen and carbon dioxide on the surface. Alternatively, it can be used with water [[electrolysis]] to generate carbon monoxide and oxygen. The oxygen is used for breathing or as oxidizer, while the carbon monoxide can be used as a moderate specific-impulse fuel (with oxygen as the oxidizer) or as a feedstock to [[hydrocarbon synthesis|generate]] higher [[hydrocarbons]] (see [[Fischer-Tropsch reaction]])

==Process==

In the presence of a suitable catalyst, the reaction takes place according to this equation:

CO2 + H2 → CO + H2O (deltaH = +9 kcal/mole)

The reactor itself is very similar to a Sabatier unit; a simple steel pipe filled with catalyst. According to experiments done by Pioneer Astronautics in Lakewood, Colorado, the best catalyst at low temperature for this reaction is silica consisting of 5% copper by weight and a smaller amount of [[nickel]]. This catalyst is exclusively selective to CO (i.e., it only produces carbon monoxide) with 60% conversion of CO2 to CO at 350o C, 150 torr, and a CO2/H2 feed ratio of 1/4.

==Applications==
===Production of oxygen===
The RWGS reaction’s chief attribute is that it, when used alongside water electrolysis, can generate any amount of oxygen from the equivalent amount of carbon dioxide with only a tiny amount of hydrogen. The hydrogen is recovered from the water via electrolysis and recycled back into the reactor’s feed end. When used with the Sabatier and water electrolysis reactions, the RWGS can provide an oxidizer/fuel (O/F) ratio of 3.5:1 (3.5 units of oxygen to 1 unit of methane) compared with 2:1 for the SE process alone. This is advantageous because a methane/oxygen engine reaches its highest specific impulse at this ratio.

However, the RWGS can be used in conjunction with water-electrolysis as an "infinite-leverage oxygen machine" to generate oxygen from carbon dioxide via a small amount of hydrogen.

Wait, I cannot fathom it being so straightforawrd.

==Disadvantages==

This reaction has an low equilibrium constant even at temperatures of 400o C , so it must be fed with either a hydrogen-rich or a carbon dioxide-rich mixture to ensure satisfactory results, or you have to increase the operating temperature (equilibrium constant is 0.5 only at 750°C). Excess hydrogen (or excess carbon dioxide) is captured from the exhaust with a filtering membrane and fed back into the reactor.
The effective catalyst depends on the operating temperature : Corean used ZnO-Al catalysts for the Camere Process at 600°C but also ZnO-Cr can be used above 600°C. The activity of both catalysts is however too low below this temperature.

==References==

R. Zubrin, The Case for Mars, pp. 153

[[Category: ISRU]]
[[Category:chemistry]]

Landing on Mars

2012-01-19T02:58:40Z

109.230.216.60: /* High Lift Vertical Landing Vehicle */

Landing on Mars is a difficult problem.

<blockquote>To date over 60% of the missions [to the Martian surface] have failed. The scientists and engineers of these undertakings use phrases like "Six Minutes of Terror," and "The Great Galactic Ghoul" to illustrate their experiences, evidence of the anxiety that's evoked by sending a robotic spacecraft to Mars — even among those who have devoted their careers to the task. But mention sending a human mission to land on the Red Planet, with payloads several factors larger than an unmanned spacecraft and the trepidation among that same group grows even larger.<ref name="MarsLanding"> http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/ </ref> </blockquote>

If we need a four hundred foot diameter parachute manufactured in space out of aluminum oxide fiber and sent to Mars in stiff deployed condition instead of being packed, we will not learn about it unless we see a need to experiment. Such a parachute might merit investigation. It would avoid opening shock and might be sufficiently heat resistant to maintain structural integrity during the entire descent in Mars' low gravity well. The larger the diameter of the parachute, the less the max g loading. So let us be honest with ourselves about all necessary colonization technology.

The expected max temperature for ballistic entry into Mars atmosphere is expected to be a thousand or more Kelvin degrees above the melting point of aluminum oxide so coating course aluminum oxide fibers with potassium oxide which decomposes at 490 Centigrade might protect the fibers through atmospheric entry by ablative cooling or it might not. A mixture of potassium and sodium oxides as a coating or Teflon as a coating are things that are conceivable. Engineers in this specialty would have a better idea.

I had no idea how to approach this before-now I'm locked and laedod.

== Another Alternative is the Sky Crane ==

<blockquote>the 2009 Mars Science Laboratory (MSL) rover, weighing 775 kilograms (versus MER at 175.4 kilograms each) requires an entirely new landing architecture. Too massive for airbags, the small-car sized rover will use a landing system dubbed the Sky Crane. "Even though some people laugh when they first see it, my personal view is that the Sky Crane is actually the most elegant system we've come up with yet, and the simplest," said Manning. MSL will use a combination of a rocket-guided entry with a heat shield, a parachute, then thrusters to slow the vehicle even more, followed by a crane-like system that lowers the rover on a cable for a soft landing directly on its wheels. Depending on the success of the Sky Crane with MSL, it's likely that this system can be scaled for larger payloads, but probably not the size needed to land humans on Mars. (See Ref #1) </blockquote>

== A Sure Way to Land on Mars ==
A sure but expensive way to land on Mars with a ten metric ton vehicle is to build a heat shield in orbit around Earth and send it to Mars as part of the spacecraft. After the heat shield slows the spacecraft, rockets bring it to a safe stop on Mars. Since Mars' atmosphere at the surface is one hundredth the density of Earth's atmosphere at the surface, make the heat shield proportionally bigger. Considering that the 12,250 pound Apollo command module was 12.8 feet in diameter, a ten metric ton Mars lander should have a 52 meter diameter heat shield. Assembled from 127 roughly hexagonal pieces about 4 meters in diameter, this would be a hexagonal heat shield instead of a round one. That should do. Each hexagonal piece would have a layer of ablative material on one side of a hexagon of aircraft grade aluminum. Aluminum t cross section extrusions would be fastened to the Aluminum sheet as stiffeners. In orbit, two hexagon sections would have their ablative sections butted against each other, protrusions fitting into cavities. A small gap would remain between the aluminum sheets. A 2 inch strip along the edge of each aluminum sheet would be pre-coated with brazing material. A 4 inch wide strip of aluminum to join them would likewise be coated with brazing material on one side. A ridge on the joining strip would fit in the gap between the aluminum hexagons. Then an iron heated to the right temperature would be placed on the joining strip and left for the right time. When the iron is removed and the piece cools the two hexagons make one piece with brazing material partially filling the gap between the two hexagons and rounding out the corner where the hexagons meet the joining strip. Likewise, a trusswork joining the stiffeners of all of the hexagons would be assembled by the same brazing technique and make the whole heat shield one strong rigid light weight piece. Some work has already been done considering robotic truss assembly on orbit. [http://www.ri.cmu.edu/publication_view.html?pub_id=1691 Light-Weight Mobile Robot for Space Station Trusswork] A cone section for the sphere-cone reentry vehicle would also need to be built or a somewhat different shaped section serving the same aerodynamic function, avoiding excessive, uncontrolled and chaotic side slip.

The advantage of sending up a ten ton vehicle, many pieces of heat shield and a robotic assembly station two make a big heat shield as compared to sending up a vehicle with heat shield and parachutes on an Ares V is that the big assembled-on-orbit heat shield would allow a 10 ton vehicle to land cargo safely on Mars while the Ares V scheme would not land cargo or people safely on Mars. Mars direct would do no better. See [http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/ The mars landing Approach: Getting Large Payloads to the Surface of the Red Planet]

Just as all economic activity in orbit so far has been done by robots, assembling a spacecraft to go to Mars should be done by robots and setting up the infrastructure for people to survive on Mars should be done by robots. There are some technical difficulties with this approach that must be addressed, but they seem likely to be amenable to solution.

=== Terminal Velocity of the Big Heat Shield Vehicle ===
For a rough estimate take as a starting point the estimated terminal velocity for the Apollo reentry vehicle. Estimate that the square of the terminal velocity is directly proportional to mass and the force of gravity and inversely proportional to air density and cross sectional area. The 10 metric ton vehicle with a 52 meter diameter heat shield should then have a terminal velocity less than 56 meters per second (125 miles per hour) at Mars' surface. If near the end of this descent a hole is burst through the bottom of the heat shield in the center right under the payload and hinges swing that portion of the heat shield out of the way, then retro rockets can fire at an altitude of 160 meters for 5.1 seconds with an acceleration of 11 meters per second squared and bring the payload to a stop about 17 meters above the heat shield that crashes into Mars. A few more seconds for horizontal maneuvering and throttling the rocket motor brings the payload safely to Mars on landing legs. A guesstimate of the required rocket delta V for this maneuver is about 68 meters per second.

== References ==
<references/>

Landing on Mars

2012-01-19T01:48:27Z

109.230.216.60: /* References */

Landing on Mars is a difficult problem.

<blockquote>To date over 60% of the missions [to the Martian surface] have failed. The scientists and engineers of these undertakings use phrases like "Six Minutes of Terror," and "The Great Galactic Ghoul" to illustrate their experiences, evidence of the anxiety that's evoked by sending a robotic spacecraft to Mars — even among those who have devoted their careers to the task. But mention sending a human mission to land on the Red Planet, with payloads several factors larger than an unmanned spacecraft and the trepidation among that same group grows even larger.<ref name="MarsLanding"> http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/ </ref> </blockquote>

If we need a four hundred foot diameter parachute manufactured in space out of aluminum oxide fiber and sent to Mars in stiff deployed condition instead of being packed, we will not learn about it unless we see a need to experiment. Such a parachute might merit investigation. It would avoid opening shock and might be sufficiently heat resistant to maintain structural integrity during the entire descent in Mars' low gravity well. The larger the diameter of the parachute, the less the max g loading. So let us be honest with ourselves about all necessary colonization technology.

The expected max temperature for ballistic entry into Mars atmosphere is expected to be a thousand or more Kelvin degrees above the melting point of aluminum oxide so coating course aluminum oxide fibers with potassium oxide which decomposes at 490 Centigrade might protect the fibers through atmospheric entry by ablative cooling or it might not. A mixture of potassium and sodium oxides as a coating or Teflon as a coating are things that are conceivable. Engineers in this specialty would have a better idea.

== High Lift Vertical Landing Vehicle ==

Another alternative with a greater probability of working, but possibly high cost, is a delta winged entry vehicle or lifting body with insulation like that on the space shuttle. The insulation would be somewhat cheaper because Mars atmospheric entry is less demanding than Earth reentry. After losing most of its orbital velocity to the atmosphere by heating the atmosphere in passing, this vehicle would fly supersonic close to the ground then ignite its rockets for landing. Then it would perform a Pugachev's Cobra<ref>http://en.wikipedia.org/wiki/Pugachev%27s_Cobra</ref> maneuver losing horizontal velocity by drag and by rocket thrust. It would then touch down on its tail. Rocket thrust directly into the supersonic slipstream of Mars' atmosphere will not work to safely land on Mars because the supersonic slipstream that the lander flies into would carry the noise of the rocket exhaust right back to the lander. The potential for the chaotic forces of this rocket noise to destabilize the lander's orientation and damage its structure rule out this technique. In the Pugachev's Cobra maneuver, rocket thrust is never directed directly into the supersonic slipstream. The rocket thrust always has a vertical component while the slipstream moves horizontally until the slip stream velocity is reduced to a negligible value.

This sort of vehicle might approach the point of entering a Pugachev's Cobra maneuver by flying horizontally near Mars' surface while increasing angle of attack to maintain lift while killing velocity. At a pitch attitude of 45 degrees there is little lift left to be gained by increasing angle of attack. This should occur at about Mach 2.5, which is about 600 meters per second on Mars. Then the rockets are ignited generating two Mars gravities of acceleration and the angle of attack is further increased past 90 degrees to generate negative lift and keep the vehicle in horizontal flight. As the speed decreases and negative lift generated by the wings decreases, the pitch angle is increased to reduce the component of rocket thrust in the vertical direction and increase the component of rocket thrust directed to braking. As the vehicle eventually slows to a stop in horizontal motion, a combination of throttling and thrust deflection reduces thrust to about 1 Mars gravity, the vehicle moves to a 90 degree pitch angle and settles on its tail. A guesstimate of the required rocket delta V for killing the last 600 meters per second and landing in this way is about 850 meters per second. This includes the amount of speed lost to atmospheric drag and very substantial gravity losses.

== Another Alternative is the Sky Crane ==

<blockquote>the 2009 Mars Science Laboratory (MSL) rover, weighing 775 kilograms (versus MER at 175.4 kilograms each) requires an entirely new landing architecture. Too massive for airbags, the small-car sized rover will use a landing system dubbed the Sky Crane. "Even though some people laugh when they first see it, my personal view is that the Sky Crane is actually the most elegant system we've come up with yet, and the simplest," said Manning. MSL will use a combination of a rocket-guided entry with a heat shield, a parachute, then thrusters to slow the vehicle even more, followed by a crane-like system that lowers the rover on a cable for a soft landing directly on its wheels. Depending on the success of the Sky Crane with MSL, it's likely that this system can be scaled for larger payloads, but probably not the size needed to land humans on Mars. (See Ref #1) </blockquote>

== A Sure Way to Land on Mars ==
A sure but expensive way to land on Mars with a ten metric ton vehicle is to build a heat shield in orbit around Earth and send it to Mars as part of the spacecraft. After the heat shield slows the spacecraft, rockets bring it to a safe stop on Mars. Since Mars' atmosphere at the surface is one hundredth the density of Earth's atmosphere at the surface, make the heat shield proportionally bigger. Considering that the 12,250 pound Apollo command module was 12.8 feet in diameter, a ten metric ton Mars lander should have a 52 meter diameter heat shield. Assembled from 127 roughly hexagonal pieces about 4 meters in diameter, this would be a hexagonal heat shield instead of a round one. That should do. Each hexagonal piece would have a layer of ablative material on one side of a hexagon of aircraft grade aluminum. Aluminum t cross section extrusions would be fastened to the Aluminum sheet as stiffeners. In orbit, two hexagon sections would have their ablative sections butted against each other, protrusions fitting into cavities. A small gap would remain between the aluminum sheets. A 2 inch strip along the edge of each aluminum sheet would be pre-coated with brazing material. A 4 inch wide strip of aluminum to join them would likewise be coated with brazing material on one side. A ridge on the joining strip would fit in the gap between the aluminum hexagons. Then an iron heated to the right temperature would be placed on the joining strip and left for the right time. When the iron is removed and the piece cools the two hexagons make one piece with brazing material partially filling the gap between the two hexagons and rounding out the corner where the hexagons meet the joining strip. Likewise, a trusswork joining the stiffeners of all of the hexagons would be assembled by the same brazing technique and make the whole heat shield one strong rigid light weight piece. Some work has already been done considering robotic truss assembly on orbit. [http://www.ri.cmu.edu/publication_view.html?pub_id=1691 Light-Weight Mobile Robot for Space Station Trusswork] A cone section for the sphere-cone reentry vehicle would also need to be built or a somewhat different shaped section serving the same aerodynamic function, avoiding excessive, uncontrolled and chaotic side slip.

The advantage of sending up a ten ton vehicle, many pieces of heat shield and a robotic assembly station two make a big heat shield as compared to sending up a vehicle with heat shield and parachutes on an Ares V is that the big assembled-on-orbit heat shield would allow a 10 ton vehicle to land cargo safely on Mars while the Ares V scheme would not land cargo or people safely on Mars. Mars direct would do no better. See [http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/ The mars landing Approach: Getting Large Payloads to the Surface of the Red Planet]

Just as all economic activity in orbit so far has been done by robots, assembling a spacecraft to go to Mars should be done by robots and setting up the infrastructure for people to survive on Mars should be done by robots. There are some technical difficulties with this approach that must be addressed, but they seem likely to be amenable to solution.

=== Terminal Velocity of the Big Heat Shield Vehicle ===
For a rough estimate take as a starting point the estimated terminal velocity for the Apollo reentry vehicle. Estimate that the square of the terminal velocity is directly proportional to mass and the force of gravity and inversely proportional to air density and cross sectional area. The 10 metric ton vehicle with a 52 meter diameter heat shield should then have a terminal velocity less than 56 meters per second (125 miles per hour) at Mars' surface. If near the end of this descent a hole is burst through the bottom of the heat shield in the center right under the payload and hinges swing that portion of the heat shield out of the way, then retro rockets can fire at an altitude of 160 meters for 5.1 seconds with an acceleration of 11 meters per second squared and bring the payload to a stop about 17 meters above the heat shield that crashes into Mars. A few more seconds for horizontal maneuvering and throttling the rocket motor brings the payload safely to Mars on landing legs. A guesstimate of the required rocket delta V for this maneuver is about 68 meters per second.

It's wondeurfl to have you on our side, haha!

Algae

2012-01-19T01:28:33Z

109.230.216.60: /* Open Issues */

[[Image:alga_and_bubbles.jpg|thumb|right|200px|Algae in algaculture with bubbles of oxygen]]

'''Algae''' are a diverse group of organisms, ranging from ten meter long kelp to [[microbes|unicellular]] dinoflagellate. These organisms are a vital link in many food chains on [[Earth]]. The farming of algae is called [[algaculture]].

==Cultivation of Algae==

===Open Pools===
Open pools are similar to the natural environment of many species of algae.

===Aerated Tanks===
Aerated tanks provide a controllable environment which can be tuned to the exact conditions needed by the target species.

==Uses of Algae==

===[[Food]]===
Algae are an excellent source of [[vitamins]], [[oil|oils]], [[fatty acids]], and [[minerals and trace elements in food|minerals]], and are eaten in many parts of the world. They can be grown in tanks filled with waste water, and aerated with CO2 from the martian [[atmosphere]]. A welcome side effect is the release of free [[oxygen]].

===[[Fertilizer]]===
Algae is currently used on Earth as a fertilizer.

===Waste Water Treatment===
Algae digest excess organic molecules and CO2.

===Chemosynthesis===
Certain species of algae can be grown to produce [[hydrogen]] and [[hydrocarbon synthesis|hydrocarbons]].

Super ecxietd to see more of this kind of stuff online.

Algae

2012-01-17T22:15:17Z

109.230.216.60: /* Waste Water Treatment */

[[Image:alga_and_bubbles.jpg|thumb|right|200px|Algae in algaculture with bubbles of oxygen]]

'''Algae''' are a diverse group of organisms, ranging from ten meter long kelp to [[microbes|unicellular]] dinoflagellate. These organisms are a vital link in many food chains on [[Earth]]. The farming of algae is called [[algaculture]].

==Cultivation of Algae==

===Open Pools===
Open pools are similar to the natural environment of many species of algae.

===Aerated Tanks===
Aerated tanks provide a controllable environment which can be tuned to the exact conditions needed by the target species.

==Uses of Algae==

===[[Food]]===
Algae are an excellent source of [[vitamins]], [[oil|oils]], [[fatty acids]], and [[minerals and trace elements in food|minerals]], and are eaten in many parts of the world. They can be grown in tanks filled with waste water, and aerated with CO2 from the martian [[atmosphere]]. A welcome side effect is the release of free [[oxygen]].

===[[Fertilizer]]===
Algae is currently used on Earth as a fertilizer.

And I thought I was the sesnbile one. Thanks for setting me straight.

==Open Issues==
*What is known about the efficiency factor of energy transformation from light energy to chemical energy? We need a [[food#Nutrition and Energy Calculations|calculation]] and a comparison with other food crop.

[[category:biospherics]]
[[category:agriculture]]

Microbes

2012-01-17T14:16:53Z

109.230.216.60: /* See also */

'''Microbes''' are microscopic organisms. On [[Earth]] microbes live almost everywhere: in [[soil]], in [[water]], even inside [[:category:animals|animals]]. On [[Mars]] there are no known microbes.

Future [[settlement|settlers]] will bring microbes from Earth to Mars. They will live inside [[greenhouse]]s, [[human]]s, and animals. Microbes are essential for many atmospheric processes, including the [[Nitrogen|Nitrogen Cycle]].

Microbes can be used in [[Biotechnology|biotechnological factories]] to produce chemical substances, for instance, proteins. Additionally, there are thoughts about using microbes for [[terraforming]].

==Possible Martian microbes==
The Martian surface is utterly sterile due to [[radiation]] and the absence of liquid [[water]]. The [[environmental conditions]] seem not to allow them to survive. Subsurface environments, however, may be favorable to microscopic life.

There are speculations about a threat towards the settlers or even towards Earth in case of return missions. And there are strong arguments against a threat. Microbes are always adapted closely to their natural host. In rare cases a microbe manages to jump from one terrestrial species to another. But this is rare. And this applies only for microbes that are already accustomed to live in hosts. The terrestrial soil microbes never jump to an animal, because they have adapted to the soil environment, and their whole metabolism depends upon this environment. With Martian microbes a jump is even more unlikely.

Furthermore, some people want to protect a possible indigenous Martian sub-surface biosphere from contamination by terrestrial microbes, which can only be avoided with an effort.

An answer from an epxert! Thanks for contributing.

Reverse Water-Gas Shift Reaction

2012-01-17T11:03:00Z

109.230.216.60: /* Disadvantages */

The '''Reverse Water-Gas Shift Reaction''' (RWGS reaction) was discovered in the 19th century as a method of producing [[water]] from [[carbon dioxide]] and [[hydrogen]], with [[carbon monoxide]] as a side product. In the context of [[manned mission|human missions]] to [[Mars]], it has been proposed as a complement to the Sabatier/water electrolysis (SE) process to produce [[methane]] and [[oxygen]] from hydrogen and carbon dioxide on the surface. Alternatively, it can be used with water [[electrolysis]] to generate carbon monoxide and oxygen. The oxygen is used for breathing or as oxidizer, while the carbon monoxide can be used as a moderate specific-impulse fuel (with oxygen as the oxidizer) or as a feedstock to [[hydrocarbon synthesis|generate]] higher [[hydrocarbons]] (see [[Fischer-Tropsch reaction]])

==Process==

In the presence of a suitable catalyst, the reaction takes place according to this equation:

CO2 + H2 → CO + H2O (deltaH = +9 kcal/mole)

The reactor itself is very similar to a Sabatier unit; a simple steel pipe filled with catalyst. According to experiments done by Pioneer Astronautics in Lakewood, Colorado, the best catalyst at low temperature for this reaction is silica consisting of 5% copper by weight and a smaller amount of [[nickel]]. This catalyst is exclusively selective to CO (i.e., it only produces carbon monoxide) with 60% conversion of CO2 to CO at 350o C, 150 torr, and a CO2/H2 feed ratio of 1/4.

==Applications==
===Production of oxygen===
The RWGS reaction’s chief attribute is that it, when used alongside water electrolysis, can generate any amount of oxygen from the equivalent amount of carbon dioxide with only a tiny amount of hydrogen. The hydrogen is recovered from the water via electrolysis and recycled back into the reactor’s feed end. When used with the Sabatier and water electrolysis reactions, the RWGS can provide an oxidizer/fuel (O/F) ratio of 3.5:1 (3.5 units of oxygen to 1 unit of methane) compared with 2:1 for the SE process alone. This is advantageous because a methane/oxygen engine reaches its highest specific impulse at this ratio.

However, the RWGS can be used in conjunction with water-electrolysis as an "infinite-leverage oxygen machine" to generate oxygen from carbon dioxide via a small amount of hydrogen.

===Production of carbon monoxide===
The side product carbon monoxide can be used to synthesize [[methane]], [[methanol]], and higher hydrocarbons such as ethylene and propylene, which are usable to produce further [[synthetic materials‎]] and for [[energy storage]]. The higher hydrocarbons are manufactured via the Fischer-Tropsch reactions, which use carbon monoxide and hydrogen as feedstocks.

==Advantages==

For the purposes of CO2 separation, the RWGS is far more efficient and requires a fraction of the power, compared to solid-oxide or molten carbonate electrolysis. It is also more rugged and reliable because it uses a simple steel pipe instead of multiple brittle tubes. For the same reason, a RWGS reactor can be scaled up (by adding more catalyst-filled pipes) to support a robotic sample return or human mission.

You're a real deep thniker. Thanks for sharing.

==References==

R. Zubrin, The Case for Mars, pp. 153

[[Category: ISRU]]
[[Category:chemistry]]

Solar concentrator

2011-12-16T04:30:49Z

109.230.216.60: /* Thermoelectric Generators */

A '''solar concentrator''' concentrates the power of the [[sun]] onto a small area. This [[energy]] is harnessed in a variety of ways. For example, a system called SCARLET is currently flying on ''Deep Space I''.

==Designs==

===Lenses===
A variety of [[lense]] designs are used to concentrate sunlight. A lense may be a simple piece of curved [[glass]] or [[plastics|plastic]], or a complex [[Fresnel lense]].

Hey, good to find someone who argees with me. GMTA.

===Fiber Optics===

==Utilization of Focused Solar Radiation==

===Photovoltaics===
Solar concentrators are often used in conjunction with [[solar panel|solar panels]] to increase the panel's output. This maximizes the efficiency of a limited number of solar panels.

===Thermal Engines===
The energy of the sun can boil liquids, causing changes in [[pressure]]. These pressure changes are harnessed by [[thermal engines]]. It is likely that liquids other than [[water]] will be used, due to the low temperatures on the surface. Carbon dioxide and carbon monoxide are both available as working fluids. Common thermal engine designs include the [[Sterling engine]] and the [[steam engine]]. Since the angular size of the sun as seen on Mars is smaller than it is on Earth, a larger mirror is needed to get the same sized image of the sun at about the same temperature as on Earth. Solar thermal engines should be capable of powering electric generators on Mars.

The paragon of undesratnding these issues is right here!

===Photosynthesis===
[[Greenhouse|Greenhouses]] are a good target for solar concentration. The natural sunlight on [[Mars]] is less than half that on [[Earth]].

===Lighting===
Concentrated sunlight can be used to light [[settlement|settlements]] during the day.

==Dangers==
Concentrated solar [[radiation]] can become hazardous in some situations.

===Radiation Damage===
If solar radiation is concentrated for use in greenhouses or settlements, the harmful parts of the electromagnetic spectrum need to be filtered.

===Vision Damage===
Looking directly into concentrated sunlight can damage vision.

===Heat Damage===
Objects passing through the focus of a solar concentrator can be exposed to intense light and extremely high temperatures.

==Maintenance effort==
The cosmic and solar [[radiation]] causes damage upon the concentrator mirrors. The particle bombardment causes blistering and foil carbonization. A lifetime of 10 years is assumed, thereafter the mirrors have to be replaced.

==External links==
*[http://www.mda.mil/mdalink/html/body/7b_photov.htm U.S. Department Of Defense: SCARLET]
*[http://adsabs.harvard.edu/abs/1985SSPRv...5...91F NASA ADS: On the performance and lifetime of solar mirror foils in space]

[[Category: Concepts]]
[[Category: Energy]]
[[Category:Lo-tech]]

Human

2011-12-14T14:21:57Z

109.230.216.60: /* What makes humans different from other species? */

The '''Human Race''' is considered the most intelligent species on [[Earth]]. If the colonization of [[Mars]] is successful, the human race will be the only known species living on more than one planet.

Cheers pal. I do appreictae the writing.

==Biological==
Adult human individuals on Earth have the following properties:
*Height: about 155..190 cm
*Weight: about 50..80 kg
*Maximum age: about 80 years
*Energy consumption by [[food]]: 6000 to 16000 kJ (1,66 to 4,44 kWh) (depends on size and activity)
*[[Air]] consumption: (to be completed)
*[[Water]] consumption: 2 to 4 liters per day
*Blood heat: 37°C
*Preferred environmental temperature: 20°C
*[[Symbiosis|Symbiotic relationship]] with a number of [[microbes|microorganisms]] (especially in the gut.)

The metabolism of human beings depends, just like [[animals]] and various microbes, on [[water]]. The human body contains about 70% water.

==Social==
The social behavior on Mars will be subject to conditions that are different from those on Earth. The following issues should be considered:

*The human brain needs frequent access to information. Experiments have revealed heavy psychological consequences after a period of information deprivation.

*A group of male individuals tend to be more [[amok|aggressive]] than a mixed group of males and females.

*Humans are social creatures, and long periods of isolation can be detrimental to health. In addition to fellow colonists, animals kept as [[pets]] can provide some level of social interaction. [[Pixel]] is a cat that has been adopted by the crews of the [[Mars Desert Research Station]].

==Facts and figures==
*"Daily Kilojoule Intake" (14-16 year old boys) while moderate active: "11900-13200" kJ <ref>[http://www.vssec.vic.edu.au/downloads/outreach/uniafworkshop/activity1astronaughtnutrition.pdf at Strathmore Secondary College: activity1astronaughtnutrition.pdf]</ref>

*"Energy expenditure of an average day for a healthy male": "2640" kcal, daily kJoule intake with "three hours of hard work": "3630" kcal <ref>[http://www.fao.org/docrep/W0073e/w0073e04.htm AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS: Human nutrition in the developing world]</ref>
 
{| border=1 align=left
|+ <big>Average Human Needs</big> <ref>Space Station Freedom Design Parameters - NASA SSP 30362 (1990)</ref>
|-
! INPUTS !! kg/person/day
|- align=left
| Oxygen
| 0.83
|- align=left
| Dry Food
| 0.62
|- align=left
| Water in Food
| 1.15
|- align=left
| [[food preparation|Food Preparation]] Water
| 0.79
|- align=left
| Drinking Water
| 1.61
|- align=left
| Oral Hygiene Water
| 0.36
|- align=left
| Hand and Face Wash Water
| 1.81
|- align=left
| Shower Water
| 5.44
|- align=left
| Clothes Wash Water
| 12.47
|- align=left
| Dish Wash Water
| 5.44
|- align=left
| Urinal/Commode Flush Water
| 0.49
|- align=left
! Total:
! 31.0 kg/person/day
|-
|}

{| border=1 align=center
|+ <big>Average Human Outputs</big> <ref>Space Station Freedom Design Parameters - NASA SSP 30362 (1990)</ref>
|-
! OUTPUTS !! kg/person/day
|- align=left
| Carbon Dioxide
| 1.00
|- align=left
| Water from Respiration and Perspiration
| 2.28
|- align=left
| [[Urine]]
| 1.50
|- align=left
| Urine Solids
| 0.06
|- align=left
| Hygiene Water
| 7.18
|- align=left
| Latent (Evaporated) Hygiene Water
| 0.44
|- align=left
| Clothes Wash Water
| 11.87
|- align=left
| Latent (Evaporated) Clothes Wash Water
| 0.60*
|- align=left
| Latent (Evaporated) Food Preparation Water
| 0.04
|- align=left
| Dish Wash Water
| 5.41
|- align=left
| Latent (Evaporated) Dish Wash Water
| 0.03
|- align=left
| Feces Solids
| 0.03
|- align=left
| Feces Water
| 0.09
|- align=left
| Sweat Solids
| 0.02
|- align=left
| Urinal and Commode Flush Water
| 0.49
|- align=left
! Total:
! 31.0 kg/person/day
|}

==Open issues==
*What is the optimum temperature in the artificial habitat to minimize the energy consumption by food (may be different at day and night, during work and leisure)?

==References==
<references/>

[[Category: Human Considerations]]

Deletion

2011-12-14T05:45:57Z

109.230.216.60: /* Request for cleanup */

Although we want to have all material due to [[Main_Page#Marspedia Policies|Marspedia Policies]] there are some cases making the deletion of articles, images or categories necessary. These are:

* Somebody creates an article, image or category with a misspelled name inadvertently. When she/he becomes aware of it, she/he wants to get rid of it.
* Two articles on the same subject are merged. Usually a [[Marspedia:Redirection|redirection]] is the right thing to do, but in certain cases one of the names might be useless.
* A category might become useless after a change in the [http://www.marspedia.org/index.php?title=Category:Main category tree].
* An article, picture or category has been posted by a vandal.
* An article or picture has been created (maybe unwittingly) in violation of copyright.

Anybody can nominate an article, image or category for deletion by just listing it in the appropriate section below. The deletion itself can only be done by a user with sysop permission. The deletion log can be viewed [http://www.marspedia.org/index.php?title=Special%3ALog&type=delete&user=&page= here].

==Articles for deletion==
*<del>[[Create an Article to this category]] (obviously inadvertently created)</del> -- article removed by [[User:Ioneill|Ioneill]] 13:29, 2 January 2008 (UTC)
* <del>[[Marspedia:Privacy policy]] (gibberish vandalism)</del> -- article removed by [[User:Ioneill|Ioneill]] 02:41, 10 November 2007 (UTC).
*<del>[[Atmsopheric processing]] -- Typo. Contents moved. Now it is a useless redirection page.</del> -- article with name typo deleted by [[User:Jarogers2001|Jarogers2001]] 03:59, 13 August 2008 (UTC)
*<S>[[Penis]]</S> (gibberish vandalism) deleted by [[User:Strangelv|Strangelv]] 10:53, 19 February 2009
*<S>[[Massage]]</S> (gibberish vandalism) deleted by [[User:Strangelv|Strangelv]] 11:29, 27 June 2009 (UTC)
*<del>[[Solar heat engine]] (redundant, see also [[User talk:Rfc#An article to delete]])</del> (author requested) deleted by [[User:Jarogers2001|Jarogers2001]] 00:10, 18 March 2010 (UTC)
*[[Otherwise Continent' Concept]] seemingly off topic, seemingly poor translation of Russian text, cites Russian lanuage web pages as sources. See [[Talk:Otherwise Continent' Concept]]
: I would like to give the author a few more days to put the article in the correct context (see also [[User talk:PPark|PPark's talk page]]). -- [[User:Rfc|Rfc]] 16:01, 6 March 2010 (UTC)
::The title is now a redirect that is not needed. There is not much reason to further consider deletion. --[[User:Farred|Farred]] 15:57, 21 September 2010 (UTC)
*<del>[[Climbing]] is seemingly a copyright violation. If it is not a violation and we remove it anyway, it is a small loss. It is not vital to our topic. It was created by User:76.114.114.75 on the 31st of August 2010. He has not made any other contribution since. See [[Talk:Climbing|the articles talk page]]. --[[User:Farred|Farred]] 16:06, 21 September 2010 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:30, 3 June 2011

*<del>[[At the USA Weight Lifting certification in Mesa AZ]] advertising -- [[User:Rfc|Rfc]] 16:44, 6 February 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
*<del>[[About to go in and take the PMP certification exam Say a prayer for me 53980]] advertising -- [[User:spriditis|spriditis]] 13:15, 9 February 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
*<del>[[Im referring to the cigarette 61]] spam -- [[User:spriditis|spriditis]] 17:39, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
*<del>[[Every fag smoked cuts at least five minutes of life on average 74]] spam -- [[User:spriditis|spriditis]] 17:39, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
*<del>[[Ladies smoking cigarette RETWEET if you do not SMOKE 14]] spam -- [[User:spriditis|spriditis]] 17:44, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
*[[Vaping or Smoking]] spam -- [[User:Spriditis|Spriditis]] 14:12, 12 August 2011 (UTC)
*[[I hate those dreams about the Student Loans Co too 71]] spam -- [[User:Spriditis|Spriditis]] 14:29, 19 August 2011 (UTC)
*[[Telecoms firm offers small business credits 4]] spam -- [[User:Spriditis|Spriditis]] 14:29, 19 August 2011 (UTC)
*[[Loans im paying for myself 24]] spam -- [[User:Spriditis|Spriditis]] 22:20, 19 August 2011 (UTC)
*[[Medical_Billing_and_Coding_to_Improve_Business_Profit]] spam -- [[User:Spriditis|Spriditis]] 18:40, 10 December 2011 (UTC)

==Images for deletion==
*<del>[[:Image:Reprap-small.jpg]] (for copyright reasons)</del> clarified -- [[User:Rfc|Rfc]] 18:07, 7 July 2008 (UTC)
* <del>[[:Image:UniversalBricks01.gif]] is no longer needed. A better picture is available instead. -- [[User:Rfc|Rfc]] 21:29, 17 October 2008 (UTC)</del> deleted by [[User:Jarogers2001|Jarogers2001]] 00:18, 18 March 2010 (UTC)

The following files were uploaded by [[user:PPark]]. I explained him that only English is allowed on Marspedia. No adequate reaction from him ever since.
* [[:File:Динамика автономизации.gif]] is pure russian regarding filename and contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:ГечвоК морфология.gif]] is pure russian regarding filename and contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:ГечвоК оси апр2009.gif]] is pure russian regarding filename and contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:TotalProfit OtherContin.gif‎]] has pure russian contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:Struct OtherContin super.gif]] has pure russian contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:Progr OtherContin super.gif‎]] has pure russian contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:CashTraces OtherContin.gif]] has pure russian contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)
* [[:File:CashFlow OtherContin.gif]] has pure russian contents. -- [[User:Rfc|Rfc]] 20:23, 11 March 2010 (UTC)

The following files were posted by adverising bot.
* [[:File:Certification 954.jpg]] advertising -- [[User:Rfc|Rfc]] 16:44, 6 February 2011 (UTC)
* [[:File:Certification 2212.jpg]] advertising -- [[User:spriditis|spriditis]] 13:15, 9 February 2011 (UTC)
* <del>[[:File:Electronic cigarette 3035.jpg]] spam -- [[User:spriditis|spriditis]] 17:39, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
* <del>[[:File:Electronic cigarette 3980.jpg]] spam -- [[User:spriditis|spriditis]] 17:39, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
* <del>[[:File:Electronic cigarette 2312.jpg]] spam -- [[User:spriditis|spriditis]] 17:44, 2 June 2011 (UTC)</del> deleted by [[User:Strangelv|Strangelv]] 18:33, 3 June 2011
* [[:File:Student_loans_991.jpg]] spam -- [[User:Spriditis|Spriditis]] 14:29, 19 August 2011 (UTC)
* [[:File:Student_loans_4409.jpg]] spam -- [[User:Spriditis|Spriditis]] 14:29, 19 August 2011 (UTC)
* [[:File:Student_loans_706.jpg]] spam -- [[User:Spriditis|Spriditis]] 22:20, 19 August 2011 (UTC)

==Categories for deletion==
*[http://www.marspedia.org/index.php?title=Category:Mirrored_from_Lunarp Category:Mirrored from Lunarp] - Created in error.
* <del>[http://www.marspedia.org/index.php?title=Category:Human_Missions Category:Human Missions] (This category is redundant with "Manned Missions", is not part of the tree, is not used with an article and thus is useless.)</del> - category removed by [[User:Ioneill|Ioneill]] 20:14, 7 November 2007 (UTC)
*<del>'''Category:MarsDrive''' - This category is not part of the tree, - is styled as if it were an article, - is not used with an article, - is a violation of GNU Free Document License (copy from wikipedia).</del> - category removed by [[User:Jarogers2001|Jarogers2001]] 22:16, 14 June 2008 (UTC)

==Redirects for deletion==
*''[[Space Suit]] (capital letter starts the second word. This is only a dead redirect.)'' -- no need to delete, redirect still operating. May delete later if required. [[User:Ioneill|Ioneill]] 22:07, 21 November 2007 (UTC)
*''[[Space Suits]] (plural. This is only a dead redirect.)'' -- redirect edited to "Space suit", may delete at a later time. [[User:Ioneill|Ioneill]] 22:07, 21 November 2007 (UTC)
*[[Mars 105]] and [[Mars-105]] (Dead redirect pages. These redirect pages have names that actually do not exist.)

Holy concise data bmtaan. Lol!