Marspedia - Recent changes [en]

Radiation sickness

RichardWSmith — Sat, 22 Aug 2026 09:52:28 GMT

Radiation measurements weighing biological damage: 1 gray = 1 J / kg of radiation absorbed.

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	*The REM (Roentgen Equivalent Man) is an older measurement of radiation. It tends to underestimate neutron damage.		*The REM (Roentgen Equivalent Man) is an older measurement of radiation. It tends to underestimate neutron damage.
	*The RAD (Radiation Absorbed Dose) is like the REM, but with the various weighting factors already cooked in. One RAD is equal to 100 ergs of energy absorbed per gram of material (tissue). 100 RAD is 1 Sv.		*The RAD (Radiation Absorbed Dose) is like the REM, but with the various weighting factors already cooked in. One RAD is equal to 100 ergs of energy absorbed per gram of material (tissue). 100 RAD is 1 Sv.
	*A Gray (Gy) is a measure of how much energy is absorbed by 1 kg of matter. If we are only looking at gamma rays and electrons, then 1 Gray = 1 Sv. Other forms of radiation do different damage to tissue, and the Sievert takes this into account.		*A Gray (Gy) is a measure of how much energy (1 joule) is absorbed by 1 kg of matter. If we are only looking at gamma rays and electrons, then 1 Gray = 1 Sv. Other forms of radiation do different damage to tissue, and the Sievert takes this into account.
	*A Sievert (Sv) is the system international measure of radiation. It is basically the Gray, but with weighting factors which take into account the dangerousness of different kinds of radiation. We will use the Sievert from this point forward.		*A Sievert (Sv) is the system international measure of radiation. It is basically the Gray, but with weighting factors which take into account the dangerousness of different kinds of radiation. We will use the Sievert from this point forward.

Radiation Hormesis

RichardWSmith — Fri, 21 Aug 2026 10:48:46 GMT

Exercising the Immune System: Put in placeholder text.

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	There is overwhelming evidence that very low levels of radiation are helpful to human health. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>		There is overwhelming evidence that very low levels of radiation are helpful to human health. <ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2477686/</ref>

			As far as a Mars habitat is concerned this is something of a moot point, since the background radiation on Mars will be ABOVE the amount where radiation hormesis occurs, unless the habitat is deep under ground (such as in a lava tube).

	==Discussion==		==Discussion==
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	===Exercising the Immune System===		===Exercising the Immune System===
			I (Rick) have heard this is a possible reason, but I've not found good references.

	===Stimulating Repair Mechanisms===		===Stimulating Repair Mechanisms===

Radiation sickness

RichardWSmith — Fri, 21 Aug 2026 10:40:33 GMT

Radiation measurements weighing biological damage: Corrected mis-understanding about what a Gray is.

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	Some people approximate this by saying the weighting factor is around 10, but as can be seen, this is an oversimplification. See the figure above.		Some people approximate this by saying the weighting factor is around 10, but as can be seen, this is an oversimplification. See the figure above right.

	===Radiation measurements weighing biological damage===		===Radiation measurements weighing biological damage===
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	*The REM (Roentgen Equivalent Man) is an older measurement of radiation. It tends to underestimate neutron damage.		*The REM (Roentgen Equivalent Man) is an older measurement of radiation. It tends to underestimate neutron damage.
	*The RAD (Radiation Absorbed Dose) is like the REM, but with the various weighting factors already cooked in. One RAD is equal to 100 ergs of energy absorbed per gram of material (tissue). 100 RAD is ~~1 Gy or~~ 1 Sv.		*The RAD (Radiation Absorbed Dose) is like the REM, but with the various weighting factors already cooked in. One RAD is equal to 100 ergs of energy absorbed per gram of material (tissue). 100 RAD is 1 Sv.
	*A Gray (Gy) is a ~~slightly out~~ of ~~date measure~~ of ~~radiation~~. ~~It has been replaced with the Sievert~~, ~~but basically one~~ Gray = 1 Sievert.		*A Gray (Gy) is a measure of how much energy is absorbed by 1 kg of matter. If we are only looking at gamma rays and electrons, then 1 Gray = 1 Sv. Other forms of radiation do different damage to tissue, and the Sievert takes this into account.
	*A Sievert (Sv) is the system international measure of radiation. It is basically the Gray, but with ~~slightly more accurate~~ weighting factors~~. To a non-specialist,~~ the ~~two measurements are identical~~. We will use the Sievert from this point forward.		*A Sievert (Sv) is the system international measure of radiation. It is basically the Gray, but with weighting factors which take into account the dangerousness of different kinds of radiation. We will use the Sievert from this point forward.

	==Lethal doses of radiation==		==Lethal doses of radiation==

List of Construction Materials

RichardWSmith — Fri, 21 Aug 2026 10:33:58 GMT

Added Concrete to list.

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	*[[Portland Cement]]		*[[Portland Cement]]
	*[[Sorel Cement]]		*[[Sorel Cement]]
			*[[Concrete]]
	*[[Carbon fiber]]		*[[Carbon fiber]]
	*[[Compressed regolith\|Compressed Regolith Blocks]]		*[[Compressed regolith\|Compressed Regolith Blocks]]

Concrete

RichardWSmith — Thu, 20 Aug 2026 17:49:04 GMT

Sulfur cement: fixed reference

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	===Sulfur cement===		===Sulfur cement===
	Waterless concrete can be produced from [[sulfur]] and [[regolith]]<ref>https://arxiv.org/pdf/1512.05461.pdf "A Novel Material for In Situ Construction on Mars:		Waterless concrete can be produced from [[sulfur]] and [[regolith]] <ref>https://arxiv.org/pdf/1512.05461.pdf</ref> "A Novel Material for In Situ Construction on Mars:

	See [[Sulphur Concrete]] for more information.		See [[Sulphur Concrete]] for more information.

Fiberglass

RichardWSmith — Thu, 20 Aug 2026 00:59:52 GMT

Fiber Reinforced Polymers: added link, as well as pointing out that fibreglass can be used in other materials.

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	===Fiber Reinforced Polymers===		===Fiber Reinforced Polymers===
	Natural or synthetic [[polymers]] are often combined with fiberglass to create a strong, yet lightweight, [[composite materials\|composite material]]. This material is often referred to as fiberglass, though technically it is a [[fiber reinforced polymer]] (FRP).		Natural or synthetic [[polymers]] are often combined with fiberglass to create a strong, yet lightweight, [[composite materials\|composite material]]. This material is often referred to as fiberglass, though technically it is a [[fiber reinforced polymer]] (FRP).

			Note that fibreglass fibres can be added to other materials (e.g. [[Sorel Cement\|Sorel Cement)]] to increase the strength.

	==Production==		==Production==

List of Construction Materials

RichardWSmith — Thu, 20 Aug 2026 00:57:01 GMT

Adjusted the order of materials, so like were closer to like.

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	*[[Brick]]		*[[Brick]]
			*[[Universal bricks]]
			*[[Portland Cement]]
			*[[Sorel Cement]]
	*[[Carbon fiber]]		*[[Carbon fiber]]
	*[[Compressed regolith\|Compressed Regolith Blocks]]		*[[Compressed regolith\|Compressed Regolith Blocks]]
			*[[Sintered regolith]]
	*[[Fiberglass]]		*[[Fiberglass]]
	*[[Glass]]		*[[Glass]]
	*[[Blacksmith\|Meteoric iron]]
	*[[Plastics]]		*[[Plastics]]
	*[[Sintered regolith]]
	*[[Portland Cement]]
	*[[Sorel Cement]]
	*[[Steel]]		*[[Steel]]
	*[[Superwood]]		*[[Superwood]]
	*[[~~Universal bricks~~]]		*[[Blacksmith\|Meteoric iron]]

	[[Category:Construction, Assembly, Maintenance]]		[[Category:Construction, Assembly, Maintenance]]

Portland Cement

RichardWSmith — Thu, 20 Aug 2026 00:53:32 GMT

fixing link.

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	"Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, (3 CaO·SiO2, and 2 CaO·SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass."		"Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, (3 CaO·SiO2, and 2 CaO·SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass."

	Limestone is a mineral created by life on Earth, and is unlikely to be found in any large amounts on Mars. Since 2/3 of the mass of Portland cement is limestone this will make it more expensive than on Earth. However, Calcium Carbonate (CaCO3) has been found formed by non-biological processes at 3 to 5% concentrations in polar soils by the Mars [[Phoenix Lander]], so we may be able to find local deposits.		Limestone is a mineral created by life on Earth, and is unlikely to be found in any large amounts on Mars. Since 2/3 of the mass of Portland cement is limestone this will make it more expensive than on Earth. However, Calcium Carbonate (CaCO3) has been found formed by non-biological processes at 3 to 5% concentrations in polar soils by the Mars [[Phoenix Mars Mission \| Phoenix Lander]], so we may be able to find local deposits.

	[[Sorel Cement]] will likely be cheaper on Mars, as well as being stronger. However, it erodes when exposed to water.		[[Sorel Cement]] will likely be cheaper on Mars, as well as being stronger. However, it erodes when exposed to water.

Portland Cement

RichardWSmith — Thu, 20 Aug 2026 00:52:31 GMT

Creating Portland cement page.

New page

Portland cement is the most common type of cement on Earth. When mixed with sand, gravel and water it forms concrete.

It is made by heating limestone (CaCO3) and clay minerals in a kiln to form clinker (small pebble like accretions) which are then ground into a powder.

The European standard for Portland cement is:

"Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, (3 CaO·SiO2, and 2 CaO·SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass."

Limestone is a mineral created by life on Earth, and is unlikely to be found in any large amounts on Mars. Since 2/3 of the mass of Portland cement is limestone this will make it more expensive than on Earth. However, Calcium Carbonate (CaCO3) has been found formed by non-biological processes at 3 to 5% concentrations in polar soils by the Mars [[Phoenix Lander]], so we may be able to find local deposits.

[[Sorel Cement]] will likely be cheaper on Mars, as well as being stronger. However, it erodes when exposed to water.

List of Construction Materials

RichardWSmith — Thu, 20 Aug 2026 00:37:00 GMT

Fixed link.

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	*[[Plastics]]		*[[Plastics]]
	*[[Sintered regolith]]		*[[Sintered regolith]]
			*[[Portland Cement]]
			*[[Sorel Cement]]
	*[[Steel]]		*[[Steel]]
	*[[Superwood]]		*[[Superwood]]

Radiation sickness

RichardWSmith — Fri, 14 Aug 2026 00:35:30 GMT

Radiation weighting factors: Made example more clear.

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	Some people approximate this by saying the weighting factor is around 10, but as can be seen, this is an oversimplification. See the figure ~~to the right~~.		Some people approximate this by saying the weighting factor is around 10, but as can be seen, this is an oversimplification. See the figure above.

	===Radiation measurements weighing biological damage===		===Radiation measurements weighing biological damage===