Radiation - Revision history

RichardWSmith: /* Types of Radiation */ Added link.

2025-11-18T01:35:10Z

Types of Radiation: Added link.

RichardWSmith: /* Limits for humans */ Formatting

2025-11-18T01:10:01Z

Limits for humans: Formatting

RichardWSmith: /* Exposure limits */ Fixed link.

2025-11-17T22:48:44Z

Exposure limits: Fixed link.

RichardWSmith: /* Exposure limits */ Added link to National Institute of Health's page on Radiation Hormesis.

2025-11-17T22:48:08Z

Exposure limits: Added link to National Institute of Health's page on Radiation Hormesis.

RichardWSmith: /* Effects of the Martian atmosphere */ Clarified sentence.

2024-10-08T04:12:57Z

Effects of the Martian atmosphere: Clarified sentence.

RichardWSmith: /* Effects of the Martian atmosphere */

2024-10-08T04:11:25Z

Effects of the Martian atmosphere

RichardWSmith: /* Effects of the Martian atmosphere */ Fixed links

2024-10-08T04:10:23Z

Effects of the Martian atmosphere: Fixed links

RichardWSmith: /* Effects of the Martian atmosphere */ Improved science and added links.

2024-10-08T04:08:46Z

Effects of the Martian atmosphere: Improved science and added links.

RichardWSmith: /* Protection */ Fixed grammar

2024-10-08T04:05:11Z

Protection: Fixed grammar

RichardWSmith: /* Protection */ Long term settlers may opt for higher rad. protection for balance.

2024-10-08T04:02:05Z

Protection: Long term settlers may opt for higher rad. protection for balance.

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 (RBE is a measure of the damage done to living tissue, relative to gamma rays)
-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>  Solar radiation includes the same radiation types, but it a higher proportion of protons and its heavy primaries have lower energy levels.  The high-energy heavy primaries in cosmic radiation can penetrate materials that effectively block lower-energy radiation<ref name=":1">Rapp D. (2006). Radiation Effects and Shielding Requirements in Human Missions to the Moon and Mars. Mars 2:46-71. <nowiki>https://doi.org/10.1555/mars.2006.0004</nowiki></ref>.
+[[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>  Solar radiation includes the same radiation types, but it a higher proportion of protons and its heavy primaries have lower energy levels.  The high-energy heavy primaries in cosmic radiation can penetrate materials that effectively block lower-energy radiation<ref name=":1">Rapp D. (2006). Radiation Effects and Shielding Requirements in Human Missions to the Moon and Mars. Mars 2:46-71. <nowiki>https://doi.org/10.1555/mars.2006.0004</nowiki></ref>.
 ==Astronaut Exposures==

← Older revision		Revision as of 01:10, 18 November 2025
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	It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time. (In fact numerous studies show health benefits from extremely low levels of radiation.) <ref>https://jnm.snmjournals.org/content/59/12/1786</ref> See [[Radiation Hormesis]]. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>		It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time. (In fact numerous studies show health benefits from extremely low levels of radiation.) <ref>https://jnm.snmjournals.org/content/59/12/1786</ref> See [[Radiation Hormesis]]. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>
		+
		+
	See also: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149023/. https://www.sciencedaily.com/releases/2017/09/170913104428.htm. https://www.ajronline.org/doi/full/10.2214/ajr.179.5.1791137. https://en.wikipedia.org/wiki/Radiation_hormesis		See also: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149023/. https://www.sciencedaily.com/releases/2017/09/170913104428.htm. https://www.ajronline.org/doi/full/10.2214/ajr.179.5.1791137. https://en.wikipedia.org/wiki/Radiation_hormesis

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 Exposure to dangerous levels of radiation causes [[radiation sickness]] and cancer.  The average exposure to  radiation on Earth due to natural sources is 6.2 mSv per year<ref name=":3">http://www.ans.org/pi/resources/dosechart/msv.php</ref>. The highest natural exposure is recorded in Ramsar, Iran, where people are exposed up to 260 mSv/y for many generations, with no reported harmful effects<ref name="Ghiassi-Nejad et al 2002">Ghiassi-Nejad et al, <i>Very high background radiation areas of Ramsar, Iran: Preliminary biological studies</i>, Health Physics 82(1):87-93 (February 2002), DOI: 10.1097/00004032-200201000-00011 [https://www.researchgate.net/publication, /11588980_Very_high_background_radiation_areas_of_Ramsar_Iran_Preliminary_biological_studies abstract]</ref>.  This is 13 times the maximum exposure allowed radiation workers each year.  Importantly, this level of radiation is what Mars settlers (living inside shelters of reasonable cost) would expect.  So the 'high' levels of the back ground radiation at Ramsar is good news for Mars settlement.<ref>https://pubmed.ncbi.nlm.nih.gov/17563407/</ref>  A recent study showed that the people living in this city showed increased immunity to gamma ray exposure, tho if this is from evolutionary adaption over many generations, or from the immune system being 'exercised' regularly is not known. <ref>https://pubmed.ncbi.nlm.nih.gov/11769138/</ref>
-It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time.  (In fact numerous studies show health benefits from extremely low levels of radiation.)  <ref>https://jnm.snmjournals.org/content/59/12/1786</ref> See [Radiation Hormesis]. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>
+It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time.  (In fact numerous studies show health benefits from extremely low levels of radiation.)  <ref>https://jnm.snmjournals.org/content/59/12/1786</ref> See [[Radiation Hormesis]]. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>
 See also:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149023/. https://www.sciencedaily.com/releases/2017/09/170913104428.htm.  https://www.ajronline.org/doi/full/10.2214/ajr.179.5.1791137.  https://en.wikipedia.org/wiki/Radiation_hormesis

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 Exposure to dangerous levels of radiation causes [[radiation sickness]] and cancer.  The average exposure to  radiation on Earth due to natural sources is 6.2 mSv per year<ref name=":3">http://www.ans.org/pi/resources/dosechart/msv.php</ref>. The highest natural exposure is recorded in Ramsar, Iran, where people are exposed up to 260 mSv/y for many generations, with no reported harmful effects<ref name="Ghiassi-Nejad et al 2002">Ghiassi-Nejad et al, <i>Very high background radiation areas of Ramsar, Iran: Preliminary biological studies</i>, Health Physics 82(1):87-93 (February 2002), DOI: 10.1097/00004032-200201000-00011 [https://www.researchgate.net/publication, /11588980_Very_high_background_radiation_areas_of_Ramsar_Iran_Preliminary_biological_studies abstract]</ref>.  This is 13 times the maximum exposure allowed radiation workers each year.  Importantly, this level of radiation is what Mars settlers (living inside shelters of reasonable cost) would expect.  So the 'high' levels of the back ground radiation at Ramsar is good news for Mars settlement.<ref>https://pubmed.ncbi.nlm.nih.gov/17563407/</ref>  A recent study showed that the people living in this city showed increased immunity to gamma ray exposure, tho if this is from evolutionary adaption over many generations, or from the immune system being 'exercised' regularly is not known. <ref>https://pubmed.ncbi.nlm.nih.gov/11769138/</ref>
-It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time.  (In fact numerous studies show health benefits from extremely low levels of radiation.)  <ref>https://jnm.snmjournals.org/content/59/12/1786</ref>  See also:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149023/. https://www.sciencedaily.com/releases/2017/09/170913104428.htm.  https://www.ajronline.org/doi/full/10.2214/ajr.179.5.1791137.  https://en.wikipedia.org/wiki/Radiation_hormesis
+It should be emphasized, that low level radiation doses spread over a long period of time (long enough that the bodies natural functions have time to repair the damage), are far less dangerous than large doses received in a short amount of time.  (In fact numerous studies show health benefits from extremely low levels of radiation.)  <ref>https://jnm.snmjournals.org/content/59/12/1786</ref> See [Radiation Hormesis]. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>
 Some people believe that ANY exposure to radiation, no matter how slight, poses some risk. Small dose - small risk of cancer. High dose - high risk of cancer.  This is the No Minimum Threshold theory of radiation dosage.  This works quite well with fast radiation doses high enough to cause cancers later in life, but the evidence is much weaker for low level does over a long period of time.  No Minimum Threshold is used by regulatory agencies when they wish to be extremely conservative about radiation risks.<ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043938/</ref> <ref>https://www.federalregister.gov/documents/2021/08/17/2021-17475/linear-no-threshold-model-and-standards-for-protection-against-radiation</ref> <ref>https://pubs.rsna.org/doi/10.1148/radiol.2511080671</ref>

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 Mars' thin atmosphere allows more [[Ultraviolet]] light to reach the surface, compared to Earth.  However, habitat structural materials and standard space suits should be sufficient to protect humans from UV radiation.<ref name=":4">Beaty DW, Snook K, Carlton A, Eppler D, Farrell B, Heldmann J,...Zeitlin C, on behalf of the Mars Human Precursor Science Steering Group. (2005). An Analysis of the Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars. Available at <nowiki>https://mepag.jpl.nasa.gov/reports/MHP_SSG_(06-02-05).pdf</nowiki></ref>
-Mars atmosphere effect depends on the considered inclination, as the incoming radiations will cross more matter if it's coming from the horizon rather than from the zenith. For inclination angles greater than ~45°, the atmospheric thickness is in the range from 20-30 g/cm2, and for lower inclination angles, the atmospherie thickness can exceed 100 g/cm2<ref name=":2" />.
+Mars atmosphere effect depends on the considered inclination, as the incoming radiations will cross more matter if it's coming from the horizon rather than from the zenith. For inclination angles greater than ~45°, the atmospheric thickness is in the range from 20-30 g/cm2, and for lower inclination angles, the atmospherie thickness can exceed 100 g/cm2<ref name=":2" />.  In other words, solar radiation is less dangerous when the sun in near the horizon.
 ===Low gravity effects on atmospheric thickness===

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 Cosmic radiation protons are likely to penetrate the atmosphere.  Cosmic ray heavy ions may fragment in the atmosphere, producing lower-mass ions that can still harm astronauts on the surface.
-Mars' thin atmosphere allows more [[Ultraviolet light]] to reach the surface, compared to Earth.  However, habitat structural materials and standard space suits should be sufficient to protect humans from UV radiation.<ref name=":4">Beaty DW, Snook K, Carlton A, Eppler D, Farrell B, Heldmann J,...Zeitlin C, on behalf of the Mars Human Precursor Science Steering Group. (2005). An Analysis of the Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars. Available at <nowiki>https://mepag.jpl.nasa.gov/reports/MHP_SSG_(06-02-05).pdf</nowiki></ref>
+Mars' thin atmosphere allows more [[Ultraviolet]] light to reach the surface, compared to Earth.  However, habitat structural materials and standard space suits should be sufficient to protect humans from UV radiation.<ref name=":4">Beaty DW, Snook K, Carlton A, Eppler D, Farrell B, Heldmann J,...Zeitlin C, on behalf of the Mars Human Precursor Science Steering Group. (2005). An Analysis of the Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars. Available at <nowiki>https://mepag.jpl.nasa.gov/reports/MHP_SSG_(06-02-05).pdf</nowiki></ref>
 Mars atmosphere effect depends on the considered inclination, as the incoming radiations will cross more matter if it's coming from the horizon rather than from the zenith. For inclination angles greater than ~45°, the atmospheric thickness is in the range from 20-30 g/cm2, and for lower inclination angles, the atmospherie thickness can exceed 100 g/cm2<ref name=":2" />.

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 ===Effects of the Martian atmosphere===
-Most Solar Proton Events (SPE) particles are low energy & will be stopped by the atmosphere before they reach the surface.  However, interactions with atmospheric particles can produce neutrons; those neutrons can reach the surface, so the health hazard is not eliminated.  However, the rare, very powerful SPE have energies of medium energy [Cosmic radiation| cosmic rays] and are a dangerous hazard.
+Most Solar Proton Events (SPE) particles are low energy & will be stopped by the atmosphere before they reach the surface.  However, interactions with atmospheric particles can produce neutrons; those neutrons can reach the surface, so the health hazard is not eliminated.  However, the rare, very powerful SPE have energies of medium energy [[Cosmic radiation| cosmic rays]] and are a dangerous hazard.
 Cosmic radiation protons are likely to penetrate the atmosphere.  Cosmic ray heavy ions may fragment in the atmosphere, producing lower-mass ions that can still harm astronauts on the surface.
-Mars' thin atmosphere allows more [Ultraviolet light] to reach the surface, compared to Earth.  However, habitat structural materials and standard space suits should be sufficient to protect humans from UV radiation.<ref name=":4">Beaty DW, Snook K, Carlton A, Eppler D, Farrell B, Heldmann J,...Zeitlin C, on behalf of the Mars Human Precursor Science Steering Group. (2005). An Analysis of the Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars. Available at <nowiki>https://mepag.jpl.nasa.gov/reports/MHP_SSG_(06-02-05).pdf</nowiki></ref>
+Mars' thin atmosphere allows more [[Ultraviolet light]] to reach the surface, compared to Earth.  However, habitat structural materials and standard space suits should be sufficient to protect humans from UV radiation.<ref name=":4">Beaty DW, Snook K, Carlton A, Eppler D, Farrell B, Heldmann J,...Zeitlin C, on behalf of the Mars Human Precursor Science Steering Group. (2005). An Analysis of the Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars. Available at <nowiki>https://mepag.jpl.nasa.gov/reports/MHP_SSG_(06-02-05).pdf</nowiki></ref>
 Mars atmosphere effect depends on the considered inclination, as the incoming radiations will cross more matter if it's coming from the horizon rather than from the zenith. For inclination angles greater than ~45°, the atmospheric thickness is in the range from 20-30 g/cm2, and for lower inclination angles, the atmospherie thickness can exceed 100 g/cm2<ref name=":2" />.

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 The use of g/cm2 can be translated into an equivalent thickness that depends on the material density.  For martian regolith at 2000 kg/m3, a thickness of 1m of regolith is 200 g/cm2.  Water (or ice) is 100 g/cm2.  So the minimum covering for a long term settlement would be 5m or more.  For water, although the radiation absorption is better the density is lower, so about the same thickness would be required for protection. <sup>(to be discussed)</sup>
-For people living on Mars for many years, they may prefer to have habitats with more than the minimum radiation protection.  For example, if people decide that 2 meters of packed soil is sufficient as minimum protection, they may wish to have 4 or 5 meters for most of the base.  This will because the settlers, may spend a significant amount of time outside the habitat, so to balance the low radiation protection when outside, they have with higher radiation protection inside.
+For people living on Mars for many years, they may prefer to have habitats with more than the minimum radiation protection.  For example, if people decide that 2 meters of packed soil is sufficient as minimum protection, they may wish to have 4 or 5 meters for most of the base.  They may spend a significant amount of time outside the habitat, so to balance the low radiation protection when outside they have with higher radiation protection inside.
 ==References==

← Older revision		Revision as of 04:02, 8 October 2024
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	The use of g/cm2 can be translated into an equivalent thickness that depends on the material density. For martian regolith at 2000 kg/m3, a thickness of 1m of regolith is 200 g/cm2. Water (or ice) is 100 g/cm2. So the minimum covering for a long term settlement would be 5m or more. For water, although the radiation absorption is better the density is lower, so about the same thickness would be required for protection. <sup>(to be discussed)</sup>		The use of g/cm2 can be translated into an equivalent thickness that depends on the material density. For martian regolith at 2000 kg/m3, a thickness of 1m of regolith is 200 g/cm2. Water (or ice) is 100 g/cm2. So the minimum covering for a long term settlement would be 5m or more. For water, although the radiation absorption is better the density is lower, so about the same thickness would be required for protection. <sup>(to be discussed)</sup>
		+
		+	For people living on Mars for many years, they may prefer to have habitats with more than the minimum radiation protection. For example, if people decide that 2 meters of packed soil is sufficient as minimum protection, they may wish to have 4 or 5 meters for most of the base. This will because the settlers, may spend a significant amount of time outside the habitat, so to balance the low radiation protection when outside, they have with higher radiation protection inside.

	==References==		==References==