Marspedia - User contributions [en]

Surface composition

2021-11-26T00:06:56Z

Kee.nethery: /* Black Rock Playa, Nevada, USAStephen Gillett (1997). Toward a Silicate-Based Molecular Nanotechnology. Retrieved 6 September 2019, from https://web.archive.org/web/20190906083332/https://foresight.org/Conferences/MNT05/Papers/Gillett1/#Sec61 */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface are primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>jpl.nasa.gov. 2012. Inspecting Soils Across Mars. [online] Available at: <https://www.jpl.nasa.gov/images/inspecting-soils-across-mars> [Accessed 18 October 2021].</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|
|
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Allen, C., Jager, K., Morris, R., Lindstrom, D., Lindstrom, M., & Lockwood, J. (1998). Martian soil stimulant available for scientific, educational study. Eos, Transactions American Geophysical Union, 79(34), 405-405. https://doi.org/10.1029/98eo00309</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Surface composition

2021-11-26T00:05:38Z

Kee.nethery: /* SNC-meteoritesP. Cattermole, Mars: The story of the Red Planet, (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1. */

Surface composition

2021-11-25T23:25:13Z

Kee.nethery: /* Viking Lander 1 & 2, Pathfinder, JSC Martian Soil SimulantAllen, C., Jager, K., Morris, R., Lindstrom, D., Lindstrom, M., & Lockwood, J. (1998). Martian soil stimulant available for scientific, educational study. Eos, Transactions American Geophysical Union, 79(34), 405-405. https://doi.org/10.1029/98eo00309 */

Ethanol

2021-11-25T21:46:00Z

Kee.nethery: /* Industrial Production from Ethylene */

[[File:Ethanol-2D-flat.svg|thumb|200x200px|Ethanol molecule]]
'''Ethanol''', also known as '''ethyl alcohol''' or '''grain alcohol''', is the most common [[alcohol]]. Its formula is C2H5OH. It is clear and colorless. Ethanol is useful mixed into gasoline because it has a higher octane number than gasoline, reducing engine knocking.<ref name=":0">[https://afdc.energy.gov/fuels/ethanol.html “Ethanol.”] n.d. U.S. Department of Energy: Alternative Fuels Data Center.</ref>

Ethanol is an ingredient in many beverages. It is a mild [[depressant]] when ingested. Besides its recreational use, ethanol is important to many industries and [[food preservation]]. Ethanol can be produced on Mars using [[In-situ resource utilization|In Situ Resources]].

==[[In-situ resource utilization|In situ Production]]==
[[File:Process-Ethanol.png|thumb|600x600px|Ethanol production Paths]]
Ethanol is usually produced from [[biomass]]. Most plant material can be transformed to produce Ethanol.<ref name=":0" />

===Fermentation===
Ethanol is most easily produced from [[sugars]] by [[yeast|yeasts]] through [[fermentation]].

===Industrial Production from Ethylene===
[[Ethylene]] can be hydrated to produce Ethanol, although the reverse process, Ethylene production from Ethanol by dehydration, may be more common on Mars. Ethanol may also be produced form CO or CO2 and Water using a copper catalyst and electrolysis<ref>Ethanol form CO and water https://www.technologyreview.com/2014/04/09/173425/a-less-resource-intensive-way-to-make-ethanol/</ref>.<ref>2020 upgraded process from CO2 https://scitechdaily.com/breakthrough-electrocatalyst-turns-carbon-dioxide-into-ethanol/</ref>

===Industrial Production via Carbon Dioxide===
Argonne National Laboratory in Lemont Illinois has an electrocatalyst that efficiently converts carbon dioxide into ethanol. <ref>Lina Chong (2021). Turning carbon dioxide into liquid fuel | Argonne National Laboratory. Anl.gov. Retrieved 25 November 2021, from https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel.</ref>

"The catalyst consists of atomically dispersed copper on a carbon-powder support. By an electrochemical reaction, this catalyst breaks down CO2 and water molecules and selectively reassembles the broken molecules into ethanol under an external electric field. The electrocatalytic selectivity, or 'Faradaic efficiency', of the process is over 90 percent. The catalyst also operates stably over extended operation at low voltage. The mechanism should also provide a foundation for development of highly efficient electrocatalysts for carbon dioxide conversion to a vast array of value-added chemicals."

CO2 is a stable molecule and transforming it into a different molecule is normally energy-intensive and costly. The electrochemical process of CO2-to-ethanol conversion using the catalyst could take advantage of the low-cost electricity available during off-peak hours. Because the process runs at low temperature and pressure, it can start and stop rapidly in response to the intermittent supply of excess electricity.

==Uses==
===Recreation and nutrition===
Ingestion of excessive ethanol in [[food]] or drink causes intoxication. It is a mild depressant, and impairs judgement and reduces inhibitions. Managed use of ethanol may be used to raise [[morale]]. Ethanol ingestion may be restricted heavily in a [[settlement]] due to the risk to oneself and others.
===Industrial Use===
Ethanol is useful as a [[fuel]]. In contrast to most other chemical [[energy]] sources (or energy vectors, in this case), ethanol is relatively non-toxic and unreactive.

Ethanol is an effective [[solvent]] for many chemicals.

===Food Preservation===
Ethanol is used to preserve [[fruits]] and other foods.
==References==
<references />
[[category:Materials]]

Ethanol

2021-11-25T21:43:20Z

Kee.nethery: /* Industrial Production via Carbon Dioxide */

Ethanol

2021-11-25T21:42:48Z

Kee.nethery: /* Fermentation */

[[File:Ethanol-2D-flat.svg|thumb|200x200px|Ethanol molecule]]
'''Ethanol''', also known as '''ethyl alcohol''' or '''grain alcohol''', is the most common [[alcohol]]. Its formula is C2H5OH. It is clear and colorless. Ethanol is useful mixed into gasoline because it has a higher octane number than gasoline, reducing engine knocking.<ref name=":0">[https://afdc.energy.gov/fuels/ethanol.html “Ethanol.”] n.d. U.S. Department of Energy: Alternative Fuels Data Center.</ref>

Ethanol is an ingredient in many beverages. It is a mild [[depressant]] when ingested. Besides its recreational use, ethanol is important to many industries and [[food preservation]]. Ethanol can be produced on Mars using [[In-situ resource utilization|In Situ Resources]].

==[[In-situ resource utilization|In situ Production]]==
[[File:Process-Ethanol.png|thumb|600x600px|Ethanol production Paths]]
Ethanol is usually produced from [[biomass]]. Most plant material can be transformed to produce Ethanol.<ref name=":0" />

===Fermentation===
Ethanol is most easily produced from [[sugars]] by [[yeast|yeasts]] through [[fermentation]].

===Industrial Production via Carbon Dioxide===
Argonne National Laboratory in Lemont Illinois has an electrocatalyst that efficiently converts carbon dioxide into ethanol. <ref>Lina Chong (2021). Turning carbon dioxide into liquid fuel | Argonne National Laboratory. Anl.gov. Retrieved 25 November 2021, from https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel.</ref>

"The catalyst consists of atomically dispersed copper on a carbon-powder support. By an electrochemical reaction, this catalyst breaks down CO2 and water molecules and selectively reassembles the broken molecules into ethanol under an external electric field. The electrocatalytic selectivity, or 'Faradaic efficiency', of the process is over 90 percent. The catalyst also operates stably over extended operation at low voltage. The mechanism should also provide a foundation for development of highly efficient electrocatalysts for carbon dioxide conversion to a vast array of value-added chemicals.

Because CO2 is a stable molecule, transforming it into a different molecule is normally energy-intensive and costly. But the electrochemical process of CO2-to-ethanol conversion using the catalyst could be coupled to the electric grid to take advantage of the low-cost electricity available from renewable sources like solar and wind during off-peak hours. Because the process runs at low temperature and pressure, it can start and stop rapidly in response to the intermittent supply of the renewable electricity."

===Industrial Production from Ethylene===
[[Ethylene]] can be hydrated to produce Ethanol, although the reverse process, Ethylene production from Ethanol by dehydration, may be more common on Mars. Ethanol may also be produced form CO or CO2 and Water using a copper catalyst and electrolysis<ref>Ethanol form CO and water https://www.technologyreview.com/2014/04/09/173425/a-less-resource-intensive-way-to-make-ethanol/</ref>.<ref>2020 upgraded process from CO2 https://scitechdaily.com/breakthrough-electrocatalyst-turns-carbon-dioxide-into-ethanol/</ref>

==Uses==
===Recreation and nutrition===
Ingestion of excessive ethanol in [[food]] or drink causes intoxication. It is a mild depressant, and impairs judgement and reduces inhibitions. Managed use of ethanol may be used to raise [[morale]]. Ethanol ingestion may be restricted heavily in a [[settlement]] due to the risk to oneself and others.
===Industrial Use===
Ethanol is useful as a [[fuel]]. In contrast to most other chemical [[energy]] sources (or energy vectors, in this case), ethanol is relatively non-toxic and unreactive.

Ethanol is an effective [[solvent]] for many chemicals.

===Food Preservation===
Ethanol is used to preserve [[fruits]] and other foods.
==References==
<references />
[[category:Materials]]

Ethanol

2021-11-25T21:23:35Z

Kee.nethery: /* Industrial Production */

Carbon dioxide

2021-11-16T21:44:38Z

Kee.nethery: /* How Submarines remove carbon dioxide Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay. */

[[File:Carbon dioxide Structural Formula V1.svg|thumb|200x200px|Carbon dioxyde molecule]]
'''Carbon dioxide'''<ref>https://en.wikipedia.org/wiki/Carbon_dioxide</ref> (''chemical formula:'' CO2) is a [[Elements on Mars|chemical substance]] that occupies about 96 % of the [[Mars|Martian]] [[atmosphere]].
__NOTOC__
Molar Mass of 12(C)+32(O2)=44

==Biological significance==
The metabolism of [[human|human beings]], [[:category:animals|animals]] and various [[microbes]] depends on the oxidation of [[carbohydrate]]s, resulting in carbon dioxide and water exhalation. [[:Category:Plants|Plants]] use the [[carbon]] from carbon dioxide to produce [[carbohydrates]] and release the [[oxygen]] back to the [[atmosphere]], completing the cycle.

:The reaction is: CO2(carbon dioxide) + 2H2O (water) + photons (light energy) → C(n)H2O(m) (carbohydrate) + O2(oxygen)+ H2O (water)<ref>[[w:Photosynthesis|Photosynthesis- https://en.wikipedia.org/wiki/Photosynthesis]]</ref>

Humans require that carbon dioxide levels be low in the air, so that CO2 in the blood can diffuse outwards into the air in the lungs. There can be plenty of oxygen in the air, but if CO2 goes much over 0.5% of the air pressure, then flow of CO2 out of the body is slowed. OSHA (Occupational Safety & Health Administration) has established a permissible Exposure Limit of 5,000 parts per million (ppm) or 0.5% of CO2 in the air, averaged over an 8 hour work day. At 10,000 ppm (1.0%) CO2 may cause drowsiness. At 4% to 5% it is immediately dangerous to life or health (gasping for breath, dizziness, confusion, headaches, shortness of breath). At 80,000 ppm (8% of the air pressure) it will cause unconsciousness and then death. These responses vary by individual (depending on how healthy they are), and on the length of the exposure. The treatment for too high CO2 concentration is to immediately move the subject to an area with low CO2, to allow the dangerous CO2 level in the blood to drop.

==Settlement atmosphere==
[[File:Colony CO2 treatment.png|thumb|600x600px]]
Carbon dioxide is required in the [[Air|settlement atmosphere]] for plant metabolism. Standard concentration on Earth is increasing, so the value is a moving target. However, a concentration between 300 ppm (0,03%) and 1,000 ppm (0,1%) is considered acceptable<ref>Carbon dioxyde concentrations<nowiki/>https://www.nap.edu/read/11170/chapter/5</ref>. Nuclear submarines have varying carbon dioxide levels that can reach 9000 ppm in normal operations, but average between 3-4000ppm<ref>High CO2 exposures: https://www.nap.edu/read/11170/chapter/5#47</ref>. A CO2 enriched environment may be beneficial for the growth of plants in [[greenhouse|greenhouses]] or [[photobioreactor|photobioreactors]].

The Sabatier process can be used in place of photosynthesis to complete the atmospheric part of the carbon cycle. [[Bioreactor#Methanotrophs|Methanotrophic]] synthesis of carbohydrates from [[methane]] would be required to complete the carbon metabolic cycle without the use of plants. Or food can be supplied from Earth or Mars for a partial cycle, where [[Methane]] from the Sabatier process can be stored for use as a propellant.

==How Submarines remove carbon dioxide <ref>Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay.</ref>==
Submarines are a fairly good analog for a Mars habitat, a sealed system that has to manufacture oxygen and remove carbon dioxide.

Submarines have two processes for removing CO2, primary extractor is powered and has no consumables, the secondary is low tech but has consumables (typically used when the primary is undergoing maintenance or repair).

Primary uses Monoethanolamine or MEA. MEA is sprayed on the air to increase the MEA surface area with the air. MEA absorbs CO2 from the air. CO2 rich MEA gets pumped into a heater. The MEA is boiled at a high pressure which causes the CO2 to distill out first. CO2 is compressed and pushed out of the boat into the sea. Submariner spouses complain about the MEA smell from the uniforms when they return home. The MEA smell permeates everything.

Secondary CO2 scrubber uses Lithium Hydroxide LiOH. Lithium Hydroxide absorbs CO2 but in a submarine it’s a one use process. The canisters need to remain sealed until they are going to be used. LiOH powder can be sprinkled around on surfaces to absorb CO2. This is the same technology used for CO2 removal in spacesuits. 
2LiOH(s) + CO2(g) -> Li2CO3(s) + H2O(g) <ref>Carbon Dioxide Removal – Thermodynamics. Nasa.gov. Retrieved 16 November 2021, from https://www.nasa.gov/pdf/519347main_AP_ST_CO2Removal_Therm.pdf.</ref> 
Although the reaction can be reversed, neither the ISS nor submarines do so.

==[[In-situ resource utilization|In situ Production]]==
CO2 will be extracted [[In-situ resource utilization|in-situ]] by [[atmospheric processing]], or from carbonate rocks to provide larger industrial quantities to feed industry<ref>https://www.nature.com/articles/ngeo971</ref> Carbonate rocks are common on Earth, but seem to be rarer on Mars. It is possible that Mars has more carbonate rock formations which are buried.

It is very likely that large amounts of CO2 will be found in local clays which will out-gas if the clay is warmed. (Some clays can hold 9% of their mass in CO2 when cold.)

==Notes on Atmosphere==
CO2 forms clouds in the Martian atmosphere, which is rare. (Most planetary atmospheres do not form clouds of its primary constituent.) Mars is so cold that CO2 freezes out in the winter, causing the planet's air pressure to fall by as much as 30%. See [[Atmosphere]] for more details.

CO2 is a [[Greenhouse gas]] and if more carbon dioxide could be outgassed from the crust somehow, the planet would warm. See [[Terraforming]] for more details.

==Concentration==
Concentration of CO2 on Earth is was 275 parts per million (ppm) in pre-industrial times. Currently it has risen above 400 ppm. Increasing concentration improves plant production rates, however the effect is non linear and reaches a peak of 20% improvement in yields at about 1,200 ppm.<ref>University of California, Agriculture and Natural ressources https://ucanr.edu/blogs/NurseryFlower/</ref> This may also be affected by pressure, if low pressure greenhouse are developed for Mars.
[[File:CO2 concentration.jpg|thumb|Effect of CO2 concentration on plant production]]

==Uses==

*[[Food preservation|Food Preservation]]

*[[Photosynthesis]] by plants in [[greenhouse]]s to create [[carbohydrates]] for plant metabolism.
*[[Synthetic materials]], [[Hydrocarbons|hydrocarbon]]<nowiki/>s using the [[Fischer-Tropsch reaction|Fischer Tropsch]] reaction process.
*[[Propellant]] production. Methane (CH4) and Oxygen (O2), through [[In-situ resource utilization|ISRU]] using the [[Sabatier process]]. The hydrogen comes from Electrolysis of water or is brought from Earth.
*[[Carbon]] using the [[Bosch reaction]] process. The Bosch reaction consumes hydrogen to produce carbon and water. The [[hydrogen]] can come from [[electrolysis]] of water.

==References==
[[Category: Biospherics]]
<references />

Carbon dioxide

2021-11-16T21:42:26Z

Kee.nethery: /* How Submarines remove carbon dioxideDestin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay. */

[[File:Carbon dioxide Structural Formula V1.svg|thumb|200x200px|Carbon dioxyde molecule]]
'''Carbon dioxide'''<ref>https://en.wikipedia.org/wiki/Carbon_dioxide</ref> (''chemical formula:'' CO2) is a [[Elements on Mars|chemical substance]] that occupies about 96 % of the [[Mars|Martian]] [[atmosphere]].
__NOTOC__
Molar Mass of 12(C)+32(O2)=44

==Biological significance==
The metabolism of [[human|human beings]], [[:category:animals|animals]] and various [[microbes]] depends on the oxidation of [[carbohydrate]]s, resulting in carbon dioxide and water exhalation. [[:Category:Plants|Plants]] use the [[carbon]] from carbon dioxide to produce [[carbohydrates]] and release the [[oxygen]] back to the [[atmosphere]], completing the cycle.

:The reaction is: CO2(carbon dioxide) + 2H2O (water) + photons (light energy) → C(n)H2O(m) (carbohydrate) + O2(oxygen)+ H2O (water)<ref>[[w:Photosynthesis|Photosynthesis- https://en.wikipedia.org/wiki/Photosynthesis]]</ref>

Humans require that carbon dioxide levels be low in the air, so that CO2 in the blood can diffuse outwards into the air in the lungs. There can be plenty of oxygen in the air, but if CO2 goes much over 0.5% of the air pressure, then flow of CO2 out of the body is slowed. OSHA (Occupational Safety & Health Administration) has established a permissible Exposure Limit of 5,000 parts per million (ppm) or 0.5% of CO2 in the air, averaged over an 8 hour work day. At 10,000 ppm (1.0%) CO2 may cause drowsiness. At 4% to 5% it is immediately dangerous to life or health (gasping for breath, dizziness, confusion, headaches, shortness of breath). At 80,000 ppm (8% of the air pressure) it will cause unconsciousness and then death. These responses vary by individual (depending on how healthy they are), and on the length of the exposure. The treatment for too high CO2 concentration is to immediately move the subject to an area with low CO2, to allow the dangerous CO2 level in the blood to drop.

==Settlement atmosphere==
[[File:Colony CO2 treatment.png|thumb|600x600px]]
Carbon dioxide is required in the [[Air|settlement atmosphere]] for plant metabolism. Standard concentration on Earth is increasing, so the value is a moving target. However, a concentration between 300 ppm (0,03%) and 1,000 ppm (0,1%) is considered acceptable<ref>Carbon dioxyde concentrations<nowiki/>https://www.nap.edu/read/11170/chapter/5</ref>. Nuclear submarines have varying carbon dioxide levels that can reach 9000 ppm in normal operations, but average between 3-4000ppm<ref>High CO2 exposures: https://www.nap.edu/read/11170/chapter/5#47</ref>. A CO2 enriched environment may be beneficial for the growth of plants in [[greenhouse|greenhouses]] or [[photobioreactor|photobioreactors]].

The Sabatier process can be used in place of photosynthesis to complete the atmospheric part of the carbon cycle. [[Bioreactor#Methanotrophs|Methanotrophic]] synthesis of carbohydrates from [[methane]] would be required to complete the carbon metabolic cycle without the use of plants. Or food can be supplied from Earth or Mars for a partial cycle, where [[Methane]] from the Sabatier process can be stored for use as a propellant.

==How Submarines remove carbon dioxide<ref>Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay.</ref>==
Submarines are a fairly good analog for a Mars habitat, a sealed system that has to manufacture oxygen and remove carbon dioxide.

Submarines have two processes for removing CO2, primary extractor is powered and has no consumables, the secondary is low tech but has consumables (typically used when the primary is undergoing maintenance or repair).

Primary uses Monoethanolamine or MEA. MEA is sprayed on the air to increase the MEA surface area with the air. MEA absorbs CO2 from the air. CO2 rich MEA gets pumped into a heater. The MEA is boiled at a high pressure which causes the CO2 to distill out first. CO2 is compressed and pushed out of the boat into the sea. Submariner spouses complain about the MEA smell from the uniforms when they return home. The MEA smell permeates everything.

Secondary CO2 scrubber uses Lithium Hydroxide LiOH. Lithium Hydroxide absorbs CO2 but in a submarine it’s a one use process. The canisters need to remain sealed until they are going to be used. LiOH powder can sprinkled around on surfaces to absorb CO2. This is the same technology used for CO2 removal in spacesuits. 
2LiOH(s) + CO2(g) -> Li2CO3(s) + H2O(g) <ref>CARBON DIOXIDE REMOVAL – THERMODYNAMICS. Nasa.gov. Retrieved 16 November 2021, from https://www.nasa.gov/pdf/519347main_AP_ST_CO2Removal_Therm.pdf.</ref> 
The reaction can be reversed

==[[In-situ resource utilization|In situ Production]]==
CO2 will be extracted [[In-situ resource utilization|in-situ]] by [[atmospheric processing]], or from carbonate rocks to provide larger industrial quantities to feed industry<ref>https://www.nature.com/articles/ngeo971</ref> Carbonate rocks are common on Earth, but seem to be rarer on Mars. It is possible that Mars has more carbonate rock formations which are buried.

It is very likely that large amounts of CO2 will be found in local clays which will out-gas if the clay is warmed. (Some clays can hold 9% of their mass in CO2 when cold.)

==Notes on Atmosphere==
CO2 forms clouds in the Martian atmosphere, which is rare. (Most planetary atmospheres do not form clouds of its primary constituent.) Mars is so cold that CO2 freezes out in the winter, causing the planet's air pressure to fall by as much as 30%. See [[Atmosphere]] for more details.

CO2 is a [[Greenhouse gas]] and if more carbon dioxide could be outgassed from the crust somehow, the planet would warm. See [[Terraforming]] for more details.

==Concentration==
Concentration of CO2 on Earth is was 275 parts per million (ppm) in pre-industrial times. Currently it has risen above 400 ppm. Increasing concentration improves plant production rates, however the effect is non linear and reaches a peak of 20% improvement in yields at about 1,200 ppm.<ref>University of California, Agriculture and Natural ressources https://ucanr.edu/blogs/NurseryFlower/</ref> This may also be affected by pressure, if low pressure greenhouse are developed for Mars.
[[File:CO2 concentration.jpg|thumb|Effect of CO2 concentration on plant production]]

==Uses==

*[[Food preservation|Food Preservation]]

*[[Photosynthesis]] by plants in [[greenhouse]]s to create [[carbohydrates]] for plant metabolism.
*[[Synthetic materials]], [[Hydrocarbons|hydrocarbon]]<nowiki/>s using the [[Fischer-Tropsch reaction|Fischer Tropsch]] reaction process.
*[[Propellant]] production. Methane (CH4) and Oxygen (O2), through [[In-situ resource utilization|ISRU]] using the [[Sabatier process]]. The hydrogen comes from Electrolysis of water or is brought from Earth.
*[[Carbon]] using the [[Bosch reaction]] process. The Bosch reaction consumes hydrogen to produce carbon and water. The [[hydrogen]] can come from [[electrolysis]] of water.

==References==
[[Category: Biospherics]]
<references />

Carbon dioxide

2021-11-16T21:41:13Z

Kee.nethery: /* How Submarines remove carbon dioxideDestin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay. */

[[File:Carbon dioxide Structural Formula V1.svg|thumb|200x200px|Carbon dioxyde molecule]]
'''Carbon dioxide'''<ref>https://en.wikipedia.org/wiki/Carbon_dioxide</ref> (''chemical formula:'' CO2) is a [[Elements on Mars|chemical substance]] that occupies about 96 % of the [[Mars|Martian]] [[atmosphere]].
__NOTOC__
Molar Mass of 12(C)+32(O2)=44

==Biological significance==
The metabolism of [[human|human beings]], [[:category:animals|animals]] and various [[microbes]] depends on the oxidation of [[carbohydrate]]s, resulting in carbon dioxide and water exhalation. [[:Category:Plants|Plants]] use the [[carbon]] from carbon dioxide to produce [[carbohydrates]] and release the [[oxygen]] back to the [[atmosphere]], completing the cycle.

:The reaction is: CO2(carbon dioxide) + 2H2O (water) + photons (light energy) → C(n)H2O(m) (carbohydrate) + O2(oxygen)+ H2O (water)<ref>[[w:Photosynthesis|Photosynthesis- https://en.wikipedia.org/wiki/Photosynthesis]]</ref>

Humans require that carbon dioxide levels be low in the air, so that CO2 in the blood can diffuse outwards into the air in the lungs. There can be plenty of oxygen in the air, but if CO2 goes much over 0.5% of the air pressure, then flow of CO2 out of the body is slowed. OSHA (Occupational Safety & Health Administration) has established a permissible Exposure Limit of 5,000 parts per million (ppm) or 0.5% of CO2 in the air, averaged over an 8 hour work day. At 10,000 ppm (1.0%) CO2 may cause drowsiness. At 4% to 5% it is immediately dangerous to life or health (gasping for breath, dizziness, confusion, headaches, shortness of breath). At 80,000 ppm (8% of the air pressure) it will cause unconsciousness and then death. These responses vary by individual (depending on how healthy they are), and on the length of the exposure. The treatment for too high CO2 concentration is to immediately move the subject to an area with low CO2, to allow the dangerous CO2 level in the blood to drop.

==Settlement atmosphere==
[[File:Colony CO2 treatment.png|thumb|600x600px]]
Carbon dioxide is required in the [[Air|settlement atmosphere]] for plant metabolism. Standard concentration on Earth is increasing, so the value is a moving target. However, a concentration between 300 ppm (0,03%) and 1,000 ppm (0,1%) is considered acceptable<ref>Carbon dioxyde concentrations<nowiki/>https://www.nap.edu/read/11170/chapter/5</ref>. Nuclear submarines have varying carbon dioxide levels that can reach 9000 ppm in normal operations, but average between 3-4000ppm<ref>High CO2 exposures: https://www.nap.edu/read/11170/chapter/5#47</ref>. A CO2 enriched environment may be beneficial for the growth of plants in [[greenhouse|greenhouses]] or [[photobioreactor|photobioreactors]].

The Sabatier process can be used in place of photosynthesis to complete the atmospheric part of the carbon cycle. [[Bioreactor#Methanotrophs|Methanotrophic]] synthesis of carbohydrates from [[methane]] would be required to complete the carbon metabolic cycle without the use of plants. Or food can be supplied from Earth or Mars for a partial cycle, where [[Methane]] from the Sabatier process can be stored for use as a propellant.

==How Submarines remove carbon dioxide<ref>Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay.</ref>==
Submarines are a fairly good analog for a Mars habitat, a sealed system that has to manufacture oxygen and remove carbon dioxide.

Submarines have two processes for removing CO2, primary extractor is powered and has no consumables, the secondary is low tech but has consumables (typically used when the primary is undergoing maintenance or repair).

Primary uses Monoethanolamine or MEA. MEA is sprayed on the air to increase the MEA surface area with the air. MEA absorbs CO2 from the air. CO2 rich MEA gets pumped into a heater. The MEA is boiled at a high pressure which causes the CO2 to distill out first. CO2 is compressed and pushed out of the boat into the sea. Submariner spouses complain about the MEA smell from the uniforms when they return home. The MEA smell permeates everything.

Secondary CO2 scrubber uses Lithium Hydroxide LiOH. Lithium Hydroxide absorbs CO2 but it’s a one use process. The canisters need to remain sealed until they are going to be used. LiOH powder can sprinkled around on surfaces to absorb CO2. This is the same technology used for CO2 removal in spacesuits. 
2LiOH(s) + CO2(g) -> Li2CO3(s) + H2O(g) <ref>CARBON DIOXIDE REMOVAL – THERMODYNAMICS. Nasa.gov. Retrieved 16 November 2021, from https://www.nasa.gov/pdf/519347main_AP_ST_CO2Removal_Therm.pdf.</ref> 
The reaction can be reversed

==[[In-situ resource utilization|In situ Production]]==
CO2 will be extracted [[In-situ resource utilization|in-situ]] by [[atmospheric processing]], or from carbonate rocks to provide larger industrial quantities to feed industry<ref>https://www.nature.com/articles/ngeo971</ref> Carbonate rocks are common on Earth, but seem to be rarer on Mars. It is possible that Mars has more carbonate rock formations which are buried.

It is very likely that large amounts of CO2 will be found in local clays which will out-gas if the clay is warmed. (Some clays can hold 9% of their mass in CO2 when cold.)

==Notes on Atmosphere==
CO2 forms clouds in the Martian atmosphere, which is rare. (Most planetary atmospheres do not form clouds of its primary constituent.) Mars is so cold that CO2 freezes out in the winter, causing the planet's air pressure to fall by as much as 30%. See [[Atmosphere]] for more details.

CO2 is a [[Greenhouse gas]] and if more carbon dioxide could be outgassed from the crust somehow, the planet would warm. See [[Terraforming]] for more details.

==Concentration==
Concentration of CO2 on Earth is was 275 parts per million (ppm) in pre-industrial times. Currently it has risen above 400 ppm. Increasing concentration improves plant production rates, however the effect is non linear and reaches a peak of 20% improvement in yields at about 1,200 ppm.<ref>University of California, Agriculture and Natural ressources https://ucanr.edu/blogs/NurseryFlower/</ref> This may also be affected by pressure, if low pressure greenhouse are developed for Mars.
[[File:CO2 concentration.jpg|thumb|Effect of CO2 concentration on plant production]]

==Uses==

*[[Food preservation|Food Preservation]]

*[[Photosynthesis]] by plants in [[greenhouse]]s to create [[carbohydrates]] for plant metabolism.
*[[Synthetic materials]], [[Hydrocarbons|hydrocarbon]]<nowiki/>s using the [[Fischer-Tropsch reaction|Fischer Tropsch]] reaction process.
*[[Propellant]] production. Methane (CH4) and Oxygen (O2), through [[In-situ resource utilization|ISRU]] using the [[Sabatier process]]. The hydrogen comes from Electrolysis of water or is brought from Earth.
*[[Carbon]] using the [[Bosch reaction]] process. The Bosch reaction consumes hydrogen to produce carbon and water. The [[hydrogen]] can come from [[electrolysis]] of water.

==References==
[[Category: Biospherics]]
<references />

Carbon dioxide

2021-11-16T21:40:23Z

Kee.nethery: /* Settlement atmosphere */

[[File:Carbon dioxide Structural Formula V1.svg|thumb|200x200px|Carbon dioxyde molecule]]
'''Carbon dioxide'''<ref>https://en.wikipedia.org/wiki/Carbon_dioxide</ref> (''chemical formula:'' CO2) is a [[Elements on Mars|chemical substance]] that occupies about 96 % of the [[Mars|Martian]] [[atmosphere]].
__NOTOC__
Molar Mass of 12(C)+32(O2)=44

==Biological significance==
The metabolism of [[human|human beings]], [[:category:animals|animals]] and various [[microbes]] depends on the oxidation of [[carbohydrate]]s, resulting in carbon dioxide and water exhalation. [[:Category:Plants|Plants]] use the [[carbon]] from carbon dioxide to produce [[carbohydrates]] and release the [[oxygen]] back to the [[atmosphere]], completing the cycle.

:The reaction is: CO2(carbon dioxide) + 2H2O (water) + photons (light energy) → C(n)H2O(m) (carbohydrate) + O2(oxygen)+ H2O (water)<ref>[[w:Photosynthesis|Photosynthesis- https://en.wikipedia.org/wiki/Photosynthesis]]</ref>

Humans require that carbon dioxide levels be low in the air, so that CO2 in the blood can diffuse outwards into the air in the lungs. There can be plenty of oxygen in the air, but if CO2 goes much over 0.5% of the air pressure, then flow of CO2 out of the body is slowed. OSHA (Occupational Safety & Health Administration) has established a permissible Exposure Limit of 5,000 parts per million (ppm) or 0.5% of CO2 in the air, averaged over an 8 hour work day. At 10,000 ppm (1.0%) CO2 may cause drowsiness. At 4% to 5% it is immediately dangerous to life or health (gasping for breath, dizziness, confusion, headaches, shortness of breath). At 80,000 ppm (8% of the air pressure) it will cause unconsciousness and then death. These responses vary by individual (depending on how healthy they are), and on the length of the exposure. The treatment for too high CO2 concentration is to immediately move the subject to an area with low CO2, to allow the dangerous CO2 level in the blood to drop.

==Settlement atmosphere==
[[File:Colony CO2 treatment.png|thumb|600x600px]]
Carbon dioxide is required in the [[Air|settlement atmosphere]] for plant metabolism. Standard concentration on Earth is increasing, so the value is a moving target. However, a concentration between 300 ppm (0,03%) and 1,000 ppm (0,1%) is considered acceptable<ref>Carbon dioxyde concentrations<nowiki/>https://www.nap.edu/read/11170/chapter/5</ref>. Nuclear submarines have varying carbon dioxide levels that can reach 9000 ppm in normal operations, but average between 3-4000ppm<ref>High CO2 exposures: https://www.nap.edu/read/11170/chapter/5#47</ref>. A CO2 enriched environment may be beneficial for the growth of plants in [[greenhouse|greenhouses]] or [[photobioreactor|photobioreactors]].

The Sabatier process can be used in place of photosynthesis to complete the atmospheric part of the carbon cycle. [[Bioreactor#Methanotrophs|Methanotrophic]] synthesis of carbohydrates from [[methane]] would be required to complete the carbon metabolic cycle without the use of plants. Or food can be supplied from Earth or Mars for a partial cycle, where [[Methane]] from the Sabatier process can be stored for use as a propellant.

==How Submarines remove carbon dioxide<ref>Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay.</ref>==
Submarines are a fairly good analog for a Mars habitat, a sealed system that has to manufacture oxygen and remove carbon dioxide.

Submarines have two processes for removing CO2, primary extractor is powered and has no consumables, the secondary is low tech but has consumables (typically used when the primary is undergoing maintenance or repair).

Primary uses Monoethanolamine or MEA. MEA is sprayed on the air to increase the MEA surface area with the air. MEA absorbs CO2 from the air. CO2 rich MEA gets pumped into a heater. The MEA is boiled at a high pressure which causes the CO2 to distill out first. CO2 is compressed and pushed out of the boat into the sea. Submariner spouses complain about the MEA smell from the uniforms when they return home. The MEA smell permeates everything.

Secondary CO2 scrubber uses Lithium Hydroxide LiOH. Lithium Hydroxide absorbs CO2 but it’s a one use process. The canisters need to remain sealed until they are going to be used. LiOH powder can sprinkled around on surfaces to absorb CO2. This is the same technology used for CO2 removal in spacesuits. 
2LiOH(s) + CO2(g) -> Li2CO3(s) + H2O(g) <ref>CARBON DIOXIDE REMOVAL – THERMODYNAMICS. Nasa.gov. Retrieved 16 November 2021, from https://www.nasa.gov/pdf/519347main_AP_ST_CO2Removal_Therm.pdf.</ref> 
The reaction can be reversed

==[[In-situ resource utilization|In situ Production]]==
CO2 will be extracted [[In-situ resource utilization|in-situ]] by [[atmospheric processing]], or from carbonate rocks to provide larger industrial quantities to feed industry<ref>https://www.nature.com/articles/ngeo971</ref> Carbonate rocks are common on Earth, but seem to be rarer on Mars. It is possible that Mars has more carbonate rock formations which are buried.

It is very likely that large amounts of CO2 will be found in local clays which will out-gas if the clay is warmed. (Some clays can hold 9% of their mass in CO2 when cold.)

==Notes on Atmosphere==
CO2 forms clouds in the Martian atmosphere, which is rare. (Most planetary atmospheres do not form clouds of its primary constituent.) Mars is so cold that CO2 freezes out in the winter, causing the planet's air pressure to fall by as much as 30%. See [[Atmosphere]] for more details.

CO2 is a [[Greenhouse gas]] and if more carbon dioxide could be outgassed from the crust somehow, the planet would warm. See [[Terraforming]] for more details.

==Concentration==
Concentration of CO2 on Earth is was 275 parts per million (ppm) in pre-industrial times. Currently it has risen above 400 ppm. Increasing concentration improves plant production rates, however the effect is non linear and reaches a peak of 20% improvement in yields at about 1,200 ppm.<ref>University of California, Agriculture and Natural ressources https://ucanr.edu/blogs/NurseryFlower/</ref> This may also be affected by pressure, if low pressure greenhouse are developed for Mars.
[[File:CO2 concentration.jpg|thumb|Effect of CO2 concentration on plant production]]

==Uses==

*[[Food preservation|Food Preservation]]

*[[Photosynthesis]] by plants in [[greenhouse]]s to create [[carbohydrates]] for plant metabolism.
*[[Synthetic materials]], [[Hydrocarbons|hydrocarbon]]<nowiki/>s using the [[Fischer-Tropsch reaction|Fischer Tropsch]] reaction process.
*[[Propellant]] production. Methane (CH4) and Oxygen (O2), through [[In-situ resource utilization|ISRU]] using the [[Sabatier process]]. The hydrogen comes from Electrolysis of water or is brought from Earth.
*[[Carbon]] using the [[Bosch reaction]] process. The Bosch reaction consumes hydrogen to produce carbon and water. The [[hydrogen]] can come from [[electrolysis]] of water.

==References==
[[Category: Biospherics]]
<references />

Oxygen

2021-11-16T21:23:50Z

Kee.nethery: /* Production */

{{element
|float=right
|elementName=Oxygen
|elementSymbol=O
|protons=8
|abundance=0.15% atmosphere 46,6% crust
}}

'''Oxygen''' (''[[Elements on Mars|periodic table]] symbol:'' O8) is a chemical element that can be found in the [[atmosphere]] and in most [[minerals]] on [[Mars]]. Almost half of the mass of the Martian crust is Oxygen, bound up in various minerals. Oxygen is created in stars from the fusion of [[Carbon]] and [[Helium]]. Oxygen has 8 protons and the most common isotope is oxygen 16. O17 and O18 exist and are stable. Oxygen needs two electrons to fill its outer electron shell, which makes it a powerful oxidizer. (Only [[Fluorine]] is a more powerful oxidizer, but Fluorine is a fairly rare element.)

[[Image:alga_and_bubbles.jpg|thumb|right|200px|Alga producing oxygen]]

==Relevance for life==
The metabolism of [[human|human beings]], [[:category:animals|animals]] and various [[microbes]] depends on oxygen. The atmosphere of Mars contains only 0,15 % oxygen, which is not enough to support animal or human life. If Oxygen is common in Mars' atmosphere, an [[Ozone]] layer will build up which will protect the surface from [[Ultraviolet]] light.

==Production==
Oxygen can be produced [[Atmospheric processing|in situ]]:

*in [[greenhouse]]s by plants.
*in [[Photobioreactor|photobioreactors]] by algae.
*by reduction of [[carbon dioxide]] from the martian atmosphere, or [[w:Carbonates_on_Mars|carbonate]] minerals via either molten salt reduction<ref>https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/57796/1/CO2OtakeREMTRev2.pdf</ref> or via [[Carbon_Dioxide_Scrubbers|MOXIE]] style solid oxide electrolysis.
*by reduction of oxide minerals, either at low temperature in aqueous solution<ref>https://link.springer.com/article/10.1007/s10800-017-1127-5</ref> or at high temperature in molten salt<ref>https://link.springer.com/article/10.1007/s10800-017-1143-5</ref>. This is required to free up metals from many ores.
*by [[electrolysis]] of [[water]]
*by the decomposition of [[Perchlorate|perchlorates]] in the soil.
*by thermal decomposition of [[water]] through the Sulfur/Iodine<ref>https://doi.org/10.1016/j.ijhydene.2006.05.013</ref> or Zinc/Sulfur/Iodine<ref>https://doi.org/10.1016/j.ijhydene.2015.11.049</ref> cycles.

==How Submarines produce oxygen<ref>Destin Sandlin (2021). How Do Nuclear Submarines Make Oxygen?- Smarter Every Day 251 [Video]. https://www.youtube.com/watch?v=g3Ud6mHdhlQ; SmarterEveryDay.</ref>==
Submarines are a fairly good analog for a Mars habitat, a sealed system that has to manufacture oxygen and remove carbon dioxide.

===Monitoring===
Submarines monitor the atmosphere in every compartment in the boat (submarine) because each location can have different amounts of humans and activity using oxygen and creating CO2. Air quality monitors will be required for each Mars habitat room. The monitoring for a specific location should be viewable in alternate locations because if things go wrong, people in a good location need to see it to fix it in a bad location.

The gasses they monitor in a submarine (measured in TORR) are: O2, CO2, H2, N2, H2O, pressure (a total of all of these). Other gasses monitored in mTORR are: CO, R114 (refrigerant), TRICH, ALIPHAT, AROMAT, BENZENE, R134A (refrigerant). These are gases used in systems that should not escape into the breathable air. For all these gasses they have calibration samples to confirm the monitors are working correctly.

For each bad gas being monitored they have hand held sniffers that detect concentrations to find a leak. Sniffers work just like a geiger counter or metal detector. The sniffer only detects relative concentration, it is not a numerical measurement. Consequently it has a small, medium, or large setting to vary sensitivity.

===Oxygen Creation===
On a submarine they use electrolysis to create oxygen. Two electrodes, positive and negative charged. Pure water is required because, for example, salt water will create chlorine gas which will kill people. On a submarine they use reverse osmosis to filter out the salt. They take pure water and add potassium hydroxide KOH as a catalyst to make the electrolysis go easier. The hydrogen they create is exhausted from the boat.

The backup method for producing oxygen is by burning a Chlorate candle (aka an Oxygen candle). Iron (Fe) and Sodium Chlorate (NaClO3). 
Fe + O2 -> Fe2O2 + heat 
heat + NaClO3 -> NaCl + O2 
Oxygen candles are used on the space station. Fires are classified in various ways. A Class Delta fire (self oxidizing fire), like an oxygen candle, cannot be extinguished, it has to burn out.

==Uses==

*[[Propellant]]. Oxygen is often chosen as an oxidizer for chemical propulsion.
*[[Air|Atmospheric component]]. The standard Earth atmosphere contains 21% Oxygen.
*Chemical reagent as an oxidizer.

==Related Articles==

[[lunarp:Oxygen|Oxygenlunarp]] on Lunarpedia.

[[category:Air]]
<references />

Dust collector

2021-11-16T21:02:58Z

Kee.nethery:

[[File:Dust collector.jpg|thumb|500x500px|A highly speculative image of an array of dust collectors feeding atmospheric compressors on Mars. Sized for 50 m3/s of martian air, or about 1 kg/s.]]
A dust collector is a device used to separate dust from air in an [[atmospheric processing]] system.
In some cases clean [[air]] is the desired result, in others, the [[Dust storms|dust]] is the object of interest.

Most dust collectors operate below atmospheric pressure with the fan on the clean side, after the dust separation system. In the thin martian atmosphere, the available pressure is very low, much lower than the standard operating pressure of dust collectors. So the fan might be required to be put on the dusty side, before the filters.

Dust collectors are filtration systems. For effective filtration of small particles they will often operate in cascade fashion, with a pre-filter and secondary filters.

Prior to the first stage the air can be routed through a torturous path with baffles. The incoming air hits the baffle and dust particles presumably fall down. This wikipedia article also states that heavy particles get flung to the outside wall and slide down to the bottom. It also mentions that smaller tube diameters give a higher speed for the air, causing greater separation. And that multiple stages of centrifugal air separation tubes cleans the air that much better.<ref>https://en.wikipedia.org/wiki/Dust_collector</ref>

In the traditional first stage, cyclonic separation, a type of inertial separation, can remove a large fraction of the heavier particles.<ref name=":0" /> To observe how a cyclone separator works, put some dirt into a glass of water and swirl it. The dirt collects in the center of the bottom of the glass. A cyclone separator puts high speed air into a vertical tube and spins the air around the edge of the tube. The particles fall down, clean air rises out.

HEPA grade filters can filter down to 5 microns, removing bacteria. However they have no effect on gases, only dust and particulate matter.<ref>https://www.hou.usra.edu/meetings/marsdust2017/pdf/6016.pdf</ref> Filters can clog over time. A way to handle that is with paddles that knock the particles off of the filter. This company has a cyclone dust extractor with a huge paper filter for the exhaust and there is a hand crank that swirls a paddle around inside the filter to knock dust off of the filter. They claim that their 1 micron filter is viable for years. The motor on top is connected to an impeller inside the casing.<ref>https://www.baileigh.com/cyclone-dust-extractor-dc-1450c</ref>

Electrostatic precipitators<ref>https://iopscience.iop.org/article/10.1088/1742-6596/327/1/012048/pdf</ref> might be more effective than filters in removing the fine particulates in the martian atmosphere, and are part of most process proposals. Electrically charge the air particles and drive them to a plate of the opposite charge. Periodically clean the plate by vibrating it. This works best with a slow air flow so that the particles have time to be charged and attracted to the plates.

Dust collectors might be used in a number of cases:

*Extraction of in situ resources from the martian atmosphere.
*Cabin filtration in vehicles.
*Airlock pump down systems.
*Interior air filtration of a settlement.
*Interior air filtration of settlement production facilities.

The background (average) dust loading of Mars is estimated at 1,8e-7 kg/m3<ref>https://pdfs.semanticscholar.org/418a/88f31b87f3d615a1f6116d31a078cfde8802.pdf</ref>. A dust collector treating 1 kg/s of martian atmosphere, about 50 m3/s, would need to remove 283 kg of dust per year. This would be sufficient to produce the propellant for 40 Starship type vehicles. So for a single vehicle about 7 kg per year would need to be removed from about 1,1 m3/s (2400 cfm).
{| class="wikitable"
|Dust collection
|
|average background
|-
|Volume flow rate
|m3/s
|50
|-
|dust loading
|kg/m3
|1.80E-07
|-
|dust capture
|kg/s
|9.00E-06
|-
|per day
|s
|86400
|-
|
|kg/day
|7.78E-01
|-
|per year
|kg/year
|283.82
|}
These figures would go up during [[dust storms]], except for a solar powered settlement that would probably need to cut back on propellant production during storms.

The MEDUSA instrument<ref>https://pdfs.semanticscholar.org/418a/88f31b87f3d615a1f6116d31a078cfde8802.pdf</ref>, part of ESA [[w:ExoMars|EXO Mars]] 2020 mission, is designed to measure in situ the dust conditions of the Martian atmosphere.

==Electrostatic dust collectors==
An alternative to cartridges and bag filters is the use of electrostatic separators, that do not require air pressure differences to operate<ref name=":0">Chepko, Ariane, Michael Swanwick, Paul Sorensen, and Darius Modarress. "Two-Stage Dust Removal System for Mars In-Situ Resource Utilization Systems: System Sizing and Trade-offs." 48th International Conference on Environmental Systems, 2018.</ref>.

==References==
<references />

Sintered regolith

2021-11-16T20:35:29Z

Kee.nethery: /* Furnace Sintering */

[[Image:UniversalBricks02.jpg|thumb|right|220px|Construction elements from sintered regolith]]

'''Sintered regolith''' has been proposed as a construction material on the Moon. This technology might be extended to Mars. [[Sintering]] is the fusion of mineral particles through the application of heat. The particles are heated just enough to induce fusion, but not enough to fully melt.

Ceramic objects are produced by sintering natural and artificial ceramics, held in place by binders that are evaporated in the sintering process. However sintering can be done directly without water. As the moon is dry water binders may be problematic. On Mars, water should be readily available and ceramic production may be possible by methods similar to those used on Earth.

==Methods==
===Laser Sintering===
Laser sintering is used in [[rapid prototyping]] applications.

===Solar Sintering===
Solar energy can be focused on the regolith to achieve the 1300 degree C temperature required for sintering.

===Microwave Sintering===
A microwave can be used to heat regolith.

===Furnace Sintering===
Large kilns are used to heat the [[regolith]] as it is held in a mould.

Furnace sintering is the classic method for producing ceramic goods on Earth. However, these are held together with binders that are evaporated during the sintering process.

On Mars, binders don't need to be added to the regolith. "Here we demonstrate that by applying exclusively Martian resources a processing route involving suspensions of mineral particles called slurries or slips can be established for manufacturing ceramics on Mars. We developed water-based slurries without the use of additives that had a 51 wt. % solid load resembling commercial porcelain slurries in respect to the particle size distribution and rheological properties. These slurries were used to slip cast discs, rings and vases that were sintered at temperatures between 1000 and 1130 °C using different sintering schedules, the latter were set-up according the results of hot-stage microscopic characterization. The microstructure, porosity and the mechanical properties were characterized by SEM, X-ray computer tomography and Weibull analysis. Our wet processing of minerals yields ceramics with complex shapes that show similar mechanical properties to porcelain and could serve as a technology for future Mars colonization. The best quality parts with completely vitrificated matrix supporting a few idiomorphic crystals are obtained at 1130 °C with 10 h dwell time with volume and linear shrinkage as much as ~62% and ~17% and a characteristic compressive strength of 51 MPa."<ref>David Karl, Franz Kamutzki, Andrea Zocca, Oliver Goerke, Jens Guenster, Aleksander Gurlo (2018) Towards the colonization of Mars by in-situ resource utilization: Slip cast ceramics from Martian soil simulant. PLoS ONE 13(10): e0204025. https://doi.org/10.1371/journal.pone.0204025</ref>

== Materials ==
Practically any material than can be produced in particle form can be sintered. Ceramics, minerals, glasses and metals are all possible candidates.

==Use==
===Construction===
Sintered Regolith blocks are a possible construction material. Further testing is needed to determine the structural characteristics of such blocks. Possibilities include [[Universal bricks]] and [[arch segments]].
===Rapid Prototyping===
Laser sintering and additive manufacturing can produce custom items. Laser sintering comprises thin, sequential layers of media are laid down, and sintered together to form the item. Additive manufacturing consists of building up products layer by layer in a semi-molten state until they set into stabilize in solid form.

==See Also==

*[[lunarp:Sintered regolith|Sintered regolith on Lunarpedialunarp]].

[[Category:Synthesis]]

Brick

2021-11-16T20:24:17Z

Kee.nethery: /* Brick Manufacturing */

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.

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.

==Material==
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.

==Brick Manufacturing==
"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.

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>

==[[Embodied energy]]==
Different types of brick require different amounts of energy to produce.
{| class="wikitable"
|+
!Materials
!Embodied energy
(MJ/kg)
!Density
(kg/m3)
!Production
|-
|Regolith
|0,5
|2000
|Regolith compressed and combined with some form of cement
|-
|Clay
|3
|2000
|Martian clay baked and fired
|-
|Plastic
|80-100
|900
|Plastic from biomass or CO2+hydrogen reactions
|-
|Glass
|15
|2500
|Silica, cleaned and with required additives
|}

==See Also==
[[Universal bricks]]

[[Category:Construction, Assembly, Maintenance]]

Brick

2021-11-16T20:17:47Z

Kee.nethery: /* Material */

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.

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.

==Material==
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.

==Brick Manufacturing==
"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.

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>

==[[Embodied energy]]==
Different types of brick require different amounts of energy to produce.
{| class="wikitable"
|+
!Materials
!Embodied energy
(MJ/kg)
!Density
(kg/m3)
!Production
|-
|Regolith
|0,5
|2000
|Regolith compressed and combined with some form of cement
|-
|Clay
|3
|2000
|Martian clay baked and fired
|-
|Plastic
|80-100
|900
|Plastic from biomass or CO2+hydrogen reactions
|-
|Glass
|15
|2500
|Silica, cleaned and with required additives
|}

==See Also==
[[Universal bricks]]

[[Category:Construction, Assembly, Maintenance]]

Air

2021-11-16T20:08:36Z

Kee.nethery: /* Carbon dioxide */

[[Image:carbon_cycle_simplified.png|thumb|right|300px|Breathing keeps the Carbon Cycle running]]

This article is for air inside a [[Settlement|Martian settlement]]. For the air outside, see [[atmosphere]].

Settlers on [[Mars]] will depend on manufactured '''air''' for breathing, since the planet's [[atmosphere]] is too thin and lacks Oxygen. This air will be provided and controlled by the settlement [[life support]] system.

Standard air on Earth is composed of Nitrogen (78%) and Oxygen (21%), with traces of other gases at 101,3 kPa (14,7 psi) of pressure.

==Gases==

===[[Oxygen]]===
[[Oxygen]] is the one essential component of any breathing gas. At sea level on Earth, the partial pressure of oxygen is about 22 kPa. Habitats on Mars will likely have a similar concentration. High oxygen concentrations and high oxygen partial pressures are possible. However, both contribute to increased flammability, so the choice of reducing pressure by increasing oxygen partial pressure has important consequences.

===Inert gases===
[[Nitrogen]] and [[argon]] are available in similar concentrations in Mars’ atmosphere and would both be suitable for use in habitats. Because inert gases slow the spread fire by absorbing heat, and nitrogen has about 65% more heat capacity per volume than argon<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/heatcap.html Molar Heat Capacities, Gases]</ref>, nitrogen may be preferred. But it is also plausible that a nitrogen/argon mix would be used since the mix would be easier to obtain, or that argon would be used, since nitrogen has other uses, such as the production of fertilizer. As argon is denser than the other gases in an atmospheric mix, a risk exists that rooms with pour air circulation might accumulate excess argon, that by displacing oxygen might increase the risk of suffocation.

===[[Carbon dioxide]]===
Carbon dioxide (CO2) is a low concentration atmospheric component in the habitat, produced by the human metabolism, plants and industrial processes. Excess carbon dioxide concentrations can produce a variety of negative health effects, even at low concentrations. But CO2 is a also a requirement for plant metabolism. CO2 level on Earth are increasing gradually, and have reached about 400 ppm, starting from an historical value of about 300 ppm. CO2 concentration in buildings is often used for fresh air control, with the upper limit set at 1000 ppm. A study on astronauts on the International Space Station found that headache risk was significantly affected by CO2 levels even at concentrations below 10,000 ppm<ref>[https://journals.lww.com/joem/Abstract/2014/05000/Relationship_Between_Carbon_Dioxide_Levels_and.4.aspx Relationship Between Carbon Dioxide Levels and Reported Headaches on the International Space Station]</ref><ref>Ben Smith (2018). Atmospheric pressure and composition - Lunar Homestead. Lunar Homestead. Retrieved 16 November 2021, from https://lunarhomestead.com/2018/04/10/atmospheric-pressure-and-composition/</ref>. Nuclear submarines can operate with up to 9000 ppm in their atmosphere.

In Mars habitats, carbon dioxide will have to be separated and removed from the air, or converted back into oxygen by plants. ISS uses a zeolite and heat style CO2 removal system. The zeolite is engineered to absorb CO2 and then when heated it releases the Carbon Dioxide.<ref>Anthony King (2018). System to rid space station of astronaut exhalations inspires Earth-based CO2 removal. ec.europa.eu. Retrieved 16 November 2021, from https://ec.europa.eu/research-and-innovation/en/horizon-magazine/system-rid-space-station-astronaut-exhalations-inspires-earth-based-co2-removal.</ref> Spacesuits use lithium hydroxide canisters for CO2 removal. Lithium hydroxide absorbs CO2.<ref>Craig Freudenrich (2000). How Space Suits Work. HowStuffWorks. Retrieved 16 November 2021, from https://science.howstuffworks.com/space-suit1.htm.</ref>

===Water vapor===
Water vapor is a product of evaporation, respiration, and combustion processes. At normal atmospheric pressure and temperature, most water condenses out of the atmosphere. However, depending on temperature and humidity, water can represent from 0 to 3% of the atmospheric mass. Water vapor is essential for comfort, and is generally presented as a value of relative humidity. Plants and people produce large amounts of water vapor, that needs to be removed to avoid excessive humidity in the settlement. Water in the atmosphere can condense out on cold surfaces, which may create maintenance problems.

==Pressure==
It may be worthwhile to keep Mars habitats at a lower pressure than we generally experience on Earth. This was done on the Apollo and Skylab missions, which both had total pressures of 5 psi (34 kPa). Robert Zubrin advocates for a Skylab-type habitat air mix on Mars, with 3.5 psi (24 kPa) O2 and 1.5 psi (10 kPa) N2<ref>Zubrin, Robert (2011). ''The Case for Mars: The Plan to Settle the Red Planet and Why We Must'' (2nd ed.) p. 159</ref>. However, the ISS operates at standard atmospheric pressure, as did the Space shuttle. There are several key considerations in determining the optimal air pressure.

===Structural stress===
Using sea level Earth air pressure, the force on each square meter of a habitat’s surface would be around 100 kN , or 10 tonnes of force per m2. Habitats on Mars will need to have high tensile strength to withstand this great force. Using a lower pressure would reduce the strain, possibly leading to more lightweight and less expensive habitats.

===Oxygen partial pressure===
The level of oxygen in the air must be high enough to supply sufficient oxygen to the bloodstream. To do this, the partial pressure of oxygen reaching the alveoli in the lungs must be comparable to what we experience on Earth. Because our lungs are saturated with water vapor, oxygen is partially crowded out at very low total pressures, so at those pressures, the partial pressure of oxygen in the air required to properly supply our lungs is actually higher.
{| class="wikitable"
|+Oxygen concentrations to provide sea level O2 absorption<ref>[https://spacecraft.ssl.umd.edu/old_site/design_lib/HSSWG_3-02.pdf Guidelines and Capabilities for Designing Human Missions]</ref>
!Total pressure (kPa)
!Oxygen partial pressure (kPa)
!Percent oxygen
|-
|25.5
|25.5
|100
|-
|34.5
|23.8
|69.0
|-
|48.3
|22.7
|47.0
|-
|62.1
|22.1
|35.5
|-
|101.4
|21.2
|21.0
|}
Since humans can survive at pressures significantly below sea level on Earth, lower oxygen pressures than shown above would certainly be tolerable. However, physical and mental performance are diminished at high altitudes on Earth, so the same is likely true for partial pressures significantly below those in the chart.

===Flammability===
Flammability is influenced by both the concentration (percentage) and partial pressure of oxygen in an environment, with concentration having the greater effect<ref>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160001047.pdf Oxygen Partial Pressure and Oxygen Concentration Flammability: Can They Be Correlated?]</ref>. So for a given partial pressure of oxygen, reducing the total pressure increases the fire risk.

===Heat transfer===
Air convection is one of the main heat transfer mechanisms. Reduced pressure air has less capacity for convective heat transfer, and added ventilation is required for work in low density air. Most plants function more efficiently if there is air movement to remove heat and evaporation from their surface. A reduction of 50% in atmospheric density corresponds to a reduction in heat capacity of the air of 50%.

===Process impacts===
A number of processes depend on atmospheric pressure to function correctly. For example, the available suctions head for pumps is a factor of atmospheric pressure. Self priming pumps will have less available head, and may require modifications or have a limited operational range. Processes requiring capillarity may also be affected by reduced pressure. Vacuum system will be less efficient as well and transport dust less efficiently. The ability of the air to absorb moisture will also be lowered by a reduced air pressure and this might affect plant growth or various processes requiring drying.

==Open Issue==

*What is known about the behaviour of dusty air under low [[gravity]]?

==References==
<references />

[[Category:Air]]

Water

2021-11-15T01:56:11Z

Kee.nethery: /* Regolith */

[[Image:GlassOfWater.jpg|thumb|200px|right|A glass is filled with drinking water.]]

'''Water''' is a chemical compound consisting of a single [[oxygen]] atom bonded to two [[hydrogen]] atoms (''chemical symbols:'' H2O). Water is essential to all known forms of life, and its unique properties make it invaluable for most industrial processes. While water in the liquid phase is abundant on [[Earth]], its icy deposits on [[Mars]] make it into a critical resource to be treasured.

==Evidence for water on Mars==

[[Image:388886main_mars_ice_226x170.jpg|thumb|226px|right|A new crater full of melting ice, as seen from the Mars Reconnaissance Orbiter.]]

[[File:PIA15090nirgalvallismariner9.jpg|thumb|226px|left|Nirgal Vallis, as seen by Mariner 9 This is one of the first images to show evidence of past water on Mars.]]

Starting in 2004, the evidence of the presence of water on Mars has been mounting.

===Past liquid water===
Mars shows evidence of extensive liquid water flowing on its surface in the past and it is the focus of many Mars missions to find out how this water has leaked away over the millennia.

The 1996 [[Mars Pathfinder]] mission discovered plentiful evidence that its landing site, [[Ares Vallis]], was once the bottom of a huge valley system eroded by ancient water.

In 2004, the [[Opportunity]] rover discovered geological markers - stratification and cross-bedding - near its landing site which pointed to significant flows of water at some time in Mars' history.<ref>Michael P. Lamb, John P. Grotzinger, John B. Southard, Nicholas J. Tosca, 2012. "Were Aqueous Ripples on Mars Formed by Flowing Brines?", Sedimentary Geology of Mars, John P. Grotzinger, Ralph E. Milliken. <nowiki>https://doi.org/10.2110/pec.12.102.0139</nowiki></ref>

The Mars Express Orbiter used [[Imaging Spectroscopy|imaging spectroscopy]] to detect hydrated minerals in 2005, strong evidence that surface water was once present in large amounts and for a long duration.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #1. Hydrated minerals – evidence of liquid water on Mars. <nowiki>https://sci.esa.int/web/mars-express/-/51821-1-hydrated-minerals-ndash-evidence-of-liquid-water-on-mars</nowiki></ref>

Further support for the historic existence of flowing water comes from the first observations made by NASA's [[Mars Reconnaissance Orbiter]] (launched in 2005) where the High Resolution Imaging Science Experiment (HiRISE) camera spotted small fractures and cracks in the Martian canyon, [[Candor Chasma]]. The cracks analyzed show signs of mineral alteration in the rock exposed - a sign that liquid water once flowed through these sub-surface pipes.

:"''What caught my eye was the bleaching or lack of dark material along the fracture. That is a sign of mineral alteration by fluids that moved through those joints. It reminded me of something I had seen during field studies in Utah, that is light-tone zones, or 'haloes,' on either side of cracks through darker sandstone''" - Dr. Chris Okubo, a geologist at the University of Arizona, Tucson.

Although this is a sign that the liquid water has since disappeared from these cracks and fractures in the canyon rock, it is interesting to find evidence for ancient water in abundance.

===Current water ice===
Today, water on Mars appears to be concentrated in Martian polar ice, suggesting Mars may once have had a warmer climate, slowly cooling as the atmosphere became a more inefficient insulator for the meager heating from the distant Sun.

In 2004 the [[Mars Express]] orbiter detected spectral evidence of water in the south pole's ice cap and the surrounding area, which ruled out the possibility that the southern ice cap consisted of only carbon dioxide ice.<ref>European Space Agency. March 17, 2004. Water at Martian south pole. https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Water_at_Martian_south_pole</ref>

In 2005, [[Mars Express]] located an area of solid water ice near the north pole.

The Phoenix lander confirmed in 2008 that water ice is not limited to the extreme polar regions.<ref>Smith, P., et al. 2009. H2O at the Phoenix Landing Site. Science: 325, 58-61.</ref>

Photos from the [[Mars Reconnaissance Orbiter]] show frozen water just below the Martian surface (see photograph). Surprisingly the location is far away from the poles (43.28 degrees north latitude, 164.22 degrees east longitude), which raises the hope of large amounts of water all over the planet.
<ref>[http://www.nasa.gov/mission_pages/MRO/news/mro20090924.html Mars Reconnaissance Orbiter Sees Ice Exposed by Meteor Impact]</ref>

====Abundance====
[[Image:MARSIS.jpg|thumb|200px|right|A MARSIS map of Mars' south pole ice deposits.]]
On March 15, 2007, [[Mars Express]]' mission control released more news of extensive frozen water discovered at the Martian [[south pole]]. These new and highly accurate measurements predict that if the ice were to be melted, the whole planet would be covered in a liquid layer 11 meters deep.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #4. Probing the polar regions. <nowiki>https://sci.esa.int/web/mars-express/-/51824-4-probing-the-polar-regions</nowiki></ref> Although it has been known for many years that the poles have an abundance of ice, it has never been measured to this degree of accuracy. The data comes from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) currently mapping the north pole to gain a better understanding of how much frozen water may be contained there. MARSIS can probe over 2 miles below the Martian surface and has found extensive layered deposits of ice.

===Current liquid water===

Future manned exploration on Mars will require a source of water whether it is in the form of ice or sub-surface [[aquifers]]. The [[Mars Express]] orbiter has uncovered some confusing measurements suggesting there may be liquid water accompanying all that ice. MARSIS bounced back data suggesting at least 90% of the layered deposits under the polar cap are indeed supplies of ice, but a thin layer resembling liquid water is also evident. It is hard to understand the existence of liquid water at the extremely low temperatures predicted. Perhaps high pressures or small geological processes may explain these observations. Another orbiter, NASA's Mars Global Surveyor, has also returned some exciting new evidence for the existence of new flows of liquid water on the Martian surface away from the frozen poles. {{science question|What pressures are required to keep water in a liquid phase at temperatures as low as that on the surface of Mars? - [[User:Ioneill|Ioneill]]}}

The [[Mars Global Surveyor]] arrived at the Red Planet on September 11, 1997 and returned a decade of data on the evolution of the planet before it was lost in November 2006 through energy loss. It was Mars' longest operational artificial satellite. The Mars Orbiter Camera (MOC) onboard revealed new deposits possibly carried as sediment by flowing water in two locations in the past 7 years (press release dated December 6, 2006)<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref>. In images taken in August 1999 and September 2006 of the same location ([[Centauri Montes]] Region), a bright deposit measuring several hundred meters long is evident in the 2006 image but not in the 1999 image. A similar feature was observed at a different location from 2001 to 2005 at [[Terra Sirenum]]. It is worth noting that both locations are in equatorial regions, not usually associated with ice or liquid water. This suggests liquid water remains a characteristic of the Mars landscape, if only sporadically. These discoveries have increased the enthusiasm for the search for [[microbes|microbial life]], but the implications for manned exploration are huge. If there are pockets of liquid water just below the surface, Mars may yet be able to provide our future pioneers with natural springs more familiar on Earth.
[[Image:Water_deposit.jpg|thumb|left|200px|Evidence from the [[Mars Global Surveyor]] MOC instrument that spurts of liquid water may sporadically flow on the Martian surface]]
However, surface water on Mars is short-lived. The Martian atmosphere is very thin (a pressure of 7 millibars, <1% that of Earth's thick atmosphere) and cold (an average global temperature of -55°C or -67F), these two factors deny any long-term existence of liquid water. Surface liquid water will quickly freeze and [[sublimation|sublime]] into the atmosphere, bypassing the [[triple point|liquid phase]]. This phase transition for water on Mars is much like the phase transition for liquid carbon dioxide on Earth when it is released from a CO2 fire extinguisher to produce dry ice snow and CO2 gas. The phase transition for H2O on the surface of Mars occurs below the "[[triple point]]" on the phase diagram so the recent observations of sediment on the surface will have been deposited very quickly by short lived "spurts" of water. Just how short-lived these spurts of water are it is unknown, but a significant volume must have created a formidable river to carry sediment several hundred meters.

At times, the humidity of the Martian atmosphere can reach 100% (at Mars' temperature and pressure). If the temperature was high, salty brines could last several minutes on the Martian surface.

Although there may be other explanations for these long "channels" of sediment, such as rock slides or wind-blown [[sand]] features, the appearance of the deposits seem very water-like. Michael Malin of Malin Space Science Systems, a mission scientist for the MOC says, "''The shapes of these deposits are what you would expect to see if the material were carried by flowing water... they have finger-like branches at the downhill end and easily diverted around small obstacles''".<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref> It is also possible that other liquids such as 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 1,3-propanediol, ethylene glycol and related liquids could be responsible for [[Recent Liquid Flow on Mars|fluid flow features]] on Mars. While such liquids would be relatively more rare than water, the resistance to freezing of such liquids and mixtures of such liquids with water would allow them to cause fluid flow effects where pure liquid water is impossible.

==Water production==
Water production on Mars for settlement use or for exploration uses can take many forms. As a prime [[In-situ resource utilization|In-situ]] resource the presence of water on Mars is one of its main attractions. Further exploration is needed to determine if the water is available in a relatively pure form, or if it will contain salts and other chemical contaminants requiring water treatment.

===Atmosphere===
The Martian [[atmosphere]] contains water vapour (which on occasion can reach 100% humidity). However, it is normally dry and very thin, which makes extracting water slow and energy intensive. With a device similar to an [[atmospheric mining|air dehumidifier]] the production of water should be feasible all over the planet's surface. An [[experimental setup#water out of the atmosphere|experimental setup]] is necessary to find out all about the viability of this approach.

"The University of Washington has designed an in situ resource utilization system to provide water to a life support system in the laboratory module of the NASA Reference Mission to Mars. This system, the Water Vapor Adsorption Reactor (WAVAR), extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular sieve. The zeolite 3A adsorbs the water vapor until nearly saturated and is then heated within a sealed chamber by microwave radiation to drive off the water for collection. The water vapor flows to a condenser where it freezes and is later liquefied for use in the life support system. In the NASA Reference Mission, water, methane, and oxygen are produced for life support and propulsion via the Sabatier/Electrolysis process from seed hydrogen brought from Earth and Martian atmospheric carbon dioxide. In order for the WAVAR system to be compatible with the NASA Reference Mission, its mass must be less than that of the seed hydrogen and cryogenic tanks apportioned for life support in the Sabatier/Electrolysis process. The WAVAR system is designed for atmospheric conditions observed by the Viking missions, which measured an average global atmospheric water vapor concentration of approx. 2 x 10-6kg/cubic meter. WAVAR performance is analyzed taking into consideration hourly and daily fluctuations in Martian ambient temperature and the corresponding effects on zeolite performance." <ref> Sergio Adan-Plaza, Kirsten Carpenter, Laila Elias, Rob Grover, Mark Hilstad, Chris Hoffman, Matt Scheider, & Adam Bruckner. (1998). Extraction of Atmospheric Water on Mars for the Mars Reference Mission. Lpi.usra.edu. Retrieved 15 November 2021, from https://www.lpi.usra.edu/publications/reports/CB-955/washington.pdf.</ref>

===Caves===
Since the discovery of [[caves]] scientists believe in the possibility of water ice on the ground of the caves. Water ice is abundant under the ground at least near the poles, and probably elsewhere too.

===Glaciers===
The [[Mars Reconnaissance Orbiter]] has found evidence of [[glacier|glaciers]] covered in regolith.<ref>http://www.nasa.gov/home/hqnews/2008/nov/HQ_08-304_MRO_BuriedGlaciers.html</ref> Radar reflection data indicates that these are not Rock Glaciers that have been previously suspected on Mars, but instead are thick glacial ice covered in a thin layer of debris. The buried glaciers lie in the [[Hellas Planitia|Hellas Basin]] region of Mars' southern hemisphere with similar aprons detected extending from cliffs in the northern hemisphere.

===Regolith===
Water is present in the martian regolith both as ice and as hydrated minerals. In addition, a recent paper has shown that a huge amount of water has been absorbed by rocks. On Earth, plate Tectonics takes these hydrated minerals and melts them, where water can return to the surface via vulcanism. On Mars the water remains in these minerals. <ref>https://science.sciencemag.org/content/early/2021/03/15/science.abc7717 - Long term drying of Mars by sequestration of Ocean-scale volumes of water in the crust</ref>

One way to obtain water from regolith is to cover a spot with a clear cover, heat it with focused sunlight (mirrors), and let the water vapor condense on the cover. Collect the condensate on the edges of the cover. At ground level the Martian atmosphere has a pressure of 6.518 millibars or 0.095 psi as compared to the Earth's sea level atmospheric pressure of 14.7 psi. <ref>Mars. Mars.nasa.gov. (1997). Retrieved 15 November 2021, from https://mars.nasa.gov/MPF/mpf/realtime/mars2.html.</ref> Boiling point of water at 6.518 millibars: 1.5 degC, 34.7 degF. <ref>Water - Boiling Points at Vacuum Pressure. Engineeringtoolbox.com. (2021). Retrieved 15 November 2021, from https://www.engineeringtoolbox.com/water-evacuation-pressure-temperature-d_1686.html.</ref>

"Excavated regolith can be processed by crushing, dry-grinding, and running it through a continuous feed electrically heated rotary kiln, heating to temperatures above 500˚C to decompose perchlorates, <ref>James D. Little (2019). 3: Aeneas Complex: A Plan For A Sustainable, Permanent 1000 Person Settlement On Mars in the book Mars colonies: Plans for Settling the Red Planet (p. 58).</ref><ref>Marvin, G., Woolaver, L., Thermal Decomposition of Perchlorates, Industrial & Engineering Chemistry Analytical Edition, 1945, Vol. 17, Iss. 8, pp. 474-476.</ref><ref>Bruck. A., Sutter, B., Ming, D., Mahaffy, P., Thermal Decomposition of Calcium Perchlorate/Iron-mineral Mixtures: Implications of the Evolved Oxygen from the Rocknest Eolian Deposit in Gale Crater, Mars., 45th Lunar and Planetary Science Conference, Mar. 2014.</ref> 
[Ca(H2O)4](ClO4)2 -> Ca(ClO4)2 + 4H2O 
oxides, sulfates, carbonates, and nitrates driving off gases and water vapor. The gases are processed through aseries of PSA equipment. The remaining regolith can be sifted and sorted, using various ore processing techniques, such as magnetic separation for iron rich minerals, and sifting to produce aggregate mixtures suitable for producing 3D printed sulfur concrete."

===Polar regions===
The martian polar regions have extensive ice caps as well as ice filled craters, such as the [[Korolev]] crater, that could serve as water sources. As the poles are usually extremely cold, sources closer to the equator would be more useful for future martian settlements. Note that permafrost has been detected at all latitudes, but above 30 degrees latitude, surface ice is found fairly often.

==Uses==

===Drinking water===
The [[human]] metabolism requires a regular intake of fresh water. Pure liquid water is non-existent on Mars but there is abundant frozen water and hydrated minerals. Since getting liquid water for use will require some industrial effort, the [[recycling]] of all excretion would provide advantages in reducing water use. There are two ways: Wastewater can be [[Potable_water_treatment|treated]], which is partially done on the [[ISS]] already. Alternatively, the water can be kept in a nearly natural cycle, using parts of the [[greenhouse]]s for [[biological wastewater treatment]].

The concentration of deuterium in Martian hydrogen and thus in Martian water is between five and thirteen ten-thousandth-parts.<ref>[http://www.sciencemag.org/content/240/4860/1767.abstract abstract in ''Science'']</ref> or about six times the relative abundance on Earth. Still this concentration is far from the 25% of the body's content of hydrogen that would need to be substituted by deuterium before there are any serious health effects. Deuterium is not a cumulative poison. At about one thousandth part of the hydrogen in Martian water, deuterium would be excreted as fast as it is consumed and would not be a health problem.

===Industrial processes===

Many industrial processes considered for a Mars settlement, in particular the production of [[methanol]] and [[methane]] and other hydrocarbons require hydrogen. This can be obtained by [[electrolysis]] or via thermolysis such as the Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2006.05.013</ref> or the Zinc/Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2015.11.049</ref>. In electrolysis or basic thermolysis, [[Oxygen O2]] is produced as a byproduct. In the Zinc/Sulfur/Iodine cycle, CO2 and H2O are inputs and the outputs are CO and H2. CO is industrially useful in the production of [[methanol]] and other [[Hydrocarbon_synthesis|hydrocarbons]], as well as in mineral refining via the [https://en.wikipedia.org/wiki/Mond_process Mond process]. The H2 can also be combined with atmospheric N2 using a [https://en.wikipedia.org/wiki/Haber_process Haber reactor] to produce [[ammonia]].

Most other processes require the use of significant quantities of water as a [[solvent]] for reagents such as [[acid]]s or [[ammonia]] or a a coolant for high temperature systems.

Power sources which rely on heat engines (such as [[nuclear power]]) require a heat sink to provide the heat differential required for the engine to run. Water or Ice make good materials for this heat sink as they are dense and have high thermal mass. The ice of [[korolev|Korolev Crater]] has been suggested as a potential heat sink sufficient to provide for colony scale power generation.

[[Deuterium]] from martian water may provide a source of fusion fuel for future energy production. Note that deuterium is 2.5 times more concentrated on Mars than on Earth, and may form a viable export.

[[Methanol]] and [[methane]] may be used to feed [[Biological_reactors|methanotrophs]] to produce food or other biologically produced industrial materials.

==See Also==

*[[Martian features that are signs of water ice]]
*[[Sublimation]]
*[[Water Infrastructure|Water infrastructure]] and waste water treatment
*"Mars: A Warmer Wetter Planet", by Jeffrey S. Kargel, ISBN 1-85233-568-8. This important book collected the evidence of water on Mars, and put to rest the idea that Mars had always been a dry planet.

==External links==

*[https://www.youtube.com/watch?v=m2ERsEXAq_s Jeffrey Plaut - Subsurface Ice - 21st Annual International Mars Society Convention]

*[http://en.wikipedia.org/wiki/Water Wikipedia page on water]
*[http://mars.jpl.nasa.gov/express/mission/sc_science_marsis02.html Searching for water with the Mars Express MARSIS instrument.]
*[https://en.wikipedia.org/wiki/Water_on_Mars Wikipedia page on water on Mars]

*[https://www.youtube.com/watch?v=RWNXJk0Y01k The Evolution of Water on Mars]
*[https://www.youtube.com/watch?v=QWcdAvFN_q0 James Wray - The Search for Water and Life on Mars (and Beyond) (November 15, 2018)]
*[https://www.youtube.com/watch?v=b4hCWIQsyps Mars: Ancient Water, Present Day Ice]
*[https://www.youtube.com/watch?v=EJk0hS4_gz4 Water on Mars and the Potential for Martian Life]
*[https://www.youtube.com/watch?v=GX9XzRyuYLc Oceans and Life on Mars]

===References===
<references />

Water

2021-11-15T01:55:28Z

Kee.nethery: two ways to extract water from regolith

[[Image:GlassOfWater.jpg|thumb|200px|right|A glass is filled with drinking water.]]

'''Water''' is a chemical compound consisting of a single [[oxygen]] atom bonded to two [[hydrogen]] atoms (''chemical symbols:'' H2O). Water is essential to all known forms of life, and its unique properties make it invaluable for most industrial processes. While water in the liquid phase is abundant on [[Earth]], its icy deposits on [[Mars]] make it into a critical resource to be treasured.

==Evidence for water on Mars==

[[Image:388886main_mars_ice_226x170.jpg|thumb|226px|right|A new crater full of melting ice, as seen from the Mars Reconnaissance Orbiter.]]

[[File:PIA15090nirgalvallismariner9.jpg|thumb|226px|left|Nirgal Vallis, as seen by Mariner 9 This is one of the first images to show evidence of past water on Mars.]]

Starting in 2004, the evidence of the presence of water on Mars has been mounting.

===Past liquid water===
Mars shows evidence of extensive liquid water flowing on its surface in the past and it is the focus of many Mars missions to find out how this water has leaked away over the millennia.

The 1996 [[Mars Pathfinder]] mission discovered plentiful evidence that its landing site, [[Ares Vallis]], was once the bottom of a huge valley system eroded by ancient water.

In 2004, the [[Opportunity]] rover discovered geological markers - stratification and cross-bedding - near its landing site which pointed to significant flows of water at some time in Mars' history.<ref>Michael P. Lamb, John P. Grotzinger, John B. Southard, Nicholas J. Tosca, 2012. "Were Aqueous Ripples on Mars Formed by Flowing Brines?", Sedimentary Geology of Mars, John P. Grotzinger, Ralph E. Milliken. <nowiki>https://doi.org/10.2110/pec.12.102.0139</nowiki></ref>

The Mars Express Orbiter used [[Imaging Spectroscopy|imaging spectroscopy]] to detect hydrated minerals in 2005, strong evidence that surface water was once present in large amounts and for a long duration.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #1. Hydrated minerals – evidence of liquid water on Mars. <nowiki>https://sci.esa.int/web/mars-express/-/51821-1-hydrated-minerals-ndash-evidence-of-liquid-water-on-mars</nowiki></ref>

Further support for the historic existence of flowing water comes from the first observations made by NASA's [[Mars Reconnaissance Orbiter]] (launched in 2005) where the High Resolution Imaging Science Experiment (HiRISE) camera spotted small fractures and cracks in the Martian canyon, [[Candor Chasma]]. The cracks analyzed show signs of mineral alteration in the rock exposed - a sign that liquid water once flowed through these sub-surface pipes.

:"''What caught my eye was the bleaching or lack of dark material along the fracture. That is a sign of mineral alteration by fluids that moved through those joints. It reminded me of something I had seen during field studies in Utah, that is light-tone zones, or 'haloes,' on either side of cracks through darker sandstone''" - Dr. Chris Okubo, a geologist at the University of Arizona, Tucson.

Although this is a sign that the liquid water has since disappeared from these cracks and fractures in the canyon rock, it is interesting to find evidence for ancient water in abundance.

===Current water ice===
Today, water on Mars appears to be concentrated in Martian polar ice, suggesting Mars may once have had a warmer climate, slowly cooling as the atmosphere became a more inefficient insulator for the meager heating from the distant Sun.

In 2004 the [[Mars Express]] orbiter detected spectral evidence of water in the south pole's ice cap and the surrounding area, which ruled out the possibility that the southern ice cap consisted of only carbon dioxide ice.<ref>European Space Agency. March 17, 2004. Water at Martian south pole. https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Water_at_Martian_south_pole</ref>

In 2005, [[Mars Express]] located an area of solid water ice near the north pole.

The Phoenix lander confirmed in 2008 that water ice is not limited to the extreme polar regions.<ref>Smith, P., et al. 2009. H2O at the Phoenix Landing Site. Science: 325, 58-61.</ref>

Photos from the [[Mars Reconnaissance Orbiter]] show frozen water just below the Martian surface (see photograph). Surprisingly the location is far away from the poles (43.28 degrees north latitude, 164.22 degrees east longitude), which raises the hope of large amounts of water all over the planet.
<ref>[http://www.nasa.gov/mission_pages/MRO/news/mro20090924.html Mars Reconnaissance Orbiter Sees Ice Exposed by Meteor Impact]</ref>

====Abundance====
[[Image:MARSIS.jpg|thumb|200px|right|A MARSIS map of Mars' south pole ice deposits.]]
On March 15, 2007, [[Mars Express]]' mission control released more news of extensive frozen water discovered at the Martian [[south pole]]. These new and highly accurate measurements predict that if the ice were to be melted, the whole planet would be covered in a liquid layer 11 meters deep.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #4. Probing the polar regions. <nowiki>https://sci.esa.int/web/mars-express/-/51824-4-probing-the-polar-regions</nowiki></ref> Although it has been known for many years that the poles have an abundance of ice, it has never been measured to this degree of accuracy. The data comes from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) currently mapping the north pole to gain a better understanding of how much frozen water may be contained there. MARSIS can probe over 2 miles below the Martian surface and has found extensive layered deposits of ice.

===Current liquid water===

Future manned exploration on Mars will require a source of water whether it is in the form of ice or sub-surface [[aquifers]]. The [[Mars Express]] orbiter has uncovered some confusing measurements suggesting there may be liquid water accompanying all that ice. MARSIS bounced back data suggesting at least 90% of the layered deposits under the polar cap are indeed supplies of ice, but a thin layer resembling liquid water is also evident. It is hard to understand the existence of liquid water at the extremely low temperatures predicted. Perhaps high pressures or small geological processes may explain these observations. Another orbiter, NASA's Mars Global Surveyor, has also returned some exciting new evidence for the existence of new flows of liquid water on the Martian surface away from the frozen poles. {{science question|What pressures are required to keep water in a liquid phase at temperatures as low as that on the surface of Mars? - [[User:Ioneill|Ioneill]]}}

The [[Mars Global Surveyor]] arrived at the Red Planet on September 11, 1997 and returned a decade of data on the evolution of the planet before it was lost in November 2006 through energy loss. It was Mars' longest operational artificial satellite. The Mars Orbiter Camera (MOC) onboard revealed new deposits possibly carried as sediment by flowing water in two locations in the past 7 years (press release dated December 6, 2006)<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref>. In images taken in August 1999 and September 2006 of the same location ([[Centauri Montes]] Region), a bright deposit measuring several hundred meters long is evident in the 2006 image but not in the 1999 image. A similar feature was observed at a different location from 2001 to 2005 at [[Terra Sirenum]]. It is worth noting that both locations are in equatorial regions, not usually associated with ice or liquid water. This suggests liquid water remains a characteristic of the Mars landscape, if only sporadically. These discoveries have increased the enthusiasm for the search for [[microbes|microbial life]], but the implications for manned exploration are huge. If there are pockets of liquid water just below the surface, Mars may yet be able to provide our future pioneers with natural springs more familiar on Earth.
[[Image:Water_deposit.jpg|thumb|left|200px|Evidence from the [[Mars Global Surveyor]] MOC instrument that spurts of liquid water may sporadically flow on the Martian surface]]
However, surface water on Mars is short-lived. The Martian atmosphere is very thin (a pressure of 7 millibars, <1% that of Earth's thick atmosphere) and cold (an average global temperature of -55°C or -67F), these two factors deny any long-term existence of liquid water. Surface liquid water will quickly freeze and [[sublimation|sublime]] into the atmosphere, bypassing the [[triple point|liquid phase]]. This phase transition for water on Mars is much like the phase transition for liquid carbon dioxide on Earth when it is released from a CO2 fire extinguisher to produce dry ice snow and CO2 gas. The phase transition for H2O on the surface of Mars occurs below the "[[triple point]]" on the phase diagram so the recent observations of sediment on the surface will have been deposited very quickly by short lived "spurts" of water. Just how short-lived these spurts of water are it is unknown, but a significant volume must have created a formidable river to carry sediment several hundred meters.

At times, the humidity of the Martian atmosphere can reach 100% (at Mars' temperature and pressure). If the temperature was high, salty brines could last several minutes on the Martian surface.

Although there may be other explanations for these long "channels" of sediment, such as rock slides or wind-blown [[sand]] features, the appearance of the deposits seem very water-like. Michael Malin of Malin Space Science Systems, a mission scientist for the MOC says, "''The shapes of these deposits are what you would expect to see if the material were carried by flowing water... they have finger-like branches at the downhill end and easily diverted around small obstacles''".<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref> It is also possible that other liquids such as 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 1,3-propanediol, ethylene glycol and related liquids could be responsible for [[Recent Liquid Flow on Mars|fluid flow features]] on Mars. While such liquids would be relatively more rare than water, the resistance to freezing of such liquids and mixtures of such liquids with water would allow them to cause fluid flow effects where pure liquid water is impossible.

==Water production==
Water production on Mars for settlement use or for exploration uses can take many forms. As a prime [[In-situ resource utilization|In-situ]] resource the presence of water on Mars is one of its main attractions. Further exploration is needed to determine if the water is available in a relatively pure form, or if it will contain salts and other chemical contaminants requiring water treatment.

===Atmosphere===
The Martian [[atmosphere]] contains water vapour (which on occasion can reach 100% humidity). However, it is normally dry and very thin, which makes extracting water slow and energy intensive. With a device similar to an [[atmospheric mining|air dehumidifier]] the production of water should be feasible all over the planet's surface. An [[experimental setup#water out of the atmosphere|experimental setup]] is necessary to find out all about the viability of this approach.

"The University of Washington has designed an in situ resource utilization system to provide water to a life support system in the laboratory module of the NASA Reference Mission to Mars. This system, the Water Vapor Adsorption Reactor (WAVAR), extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular sieve. The zeolite 3A adsorbs the water vapor until nearly saturated and is then heated within a sealed chamber by microwave radiation to drive off the water for collection. The water vapor flows to a condenser where it freezes and is later liquefied for use in the life support system. In the NASA Reference Mission, water, methane, and oxygen are produced for life support and propulsion via the Sabatier/Electrolysis process from seed hydrogen brought from Earth and Martian atmospheric carbon dioxide. In order for the WAVAR system to be compatible with the NASA Reference Mission, its mass must be less than that of the seed hydrogen and cryogenic tanks apportioned for life support in the Sabatier/Electrolysis process. The WAVAR system is designed for atmospheric conditions observed by the Viking missions, which measured an average global atmospheric water vapor concentration of approx. 2 x 10-6kg/cubic meter. WAVAR performance is analyzed taking into consideration hourly and daily fluctuations in Martian ambient temperature and the corresponding effects on zeolite performance." <ref> Sergio Adan-Plaza, Kirsten Carpenter, Laila Elias, Rob Grover, Mark Hilstad, Chris Hoffman, Matt Scheider, & Adam Bruckner. (1998). Extraction of Atmospheric Water on Mars for the Mars Reference Mission. Lpi.usra.edu. Retrieved 15 November 2021, from https://www.lpi.usra.edu/publications/reports/CB-955/washington.pdf.</ref>

===Caves===
Since the discovery of [[caves]] scientists believe in the possibility of water ice on the ground of the caves. Water ice is abundant under the ground at least near the poles, and probably elsewhere too.

===Glaciers===
The [[Mars Reconnaissance Orbiter]] has found evidence of [[glacier|glaciers]] covered in regolith.<ref>http://www.nasa.gov/home/hqnews/2008/nov/HQ_08-304_MRO_BuriedGlaciers.html</ref> Radar reflection data indicates that these are not Rock Glaciers that have been previously suspected on Mars, but instead are thick glacial ice covered in a thin layer of debris. The buried glaciers lie in the [[Hellas Planitia|Hellas Basin]] region of Mars' southern hemisphere with similar aprons detected extending from cliffs in the northern hemisphere.

===Regolith===
Water is present in the martian regolith both as ice and as hydrated minerals. In addition, a recent paper has shown that a huge amount of water has been absorbed by rocks. On Earth, plate Tectonics takes these hydrated minerals and melts them, where water can return to the surface via vulcanism. On Mars the water remains in these minerals. <ref>https://science.sciencemag.org/content/early/2021/03/15/science.abc7717 - Long term drying of Mars by sequestration of Ocean-scale volumes of water in the crust</ref>

One way to obtain water from regolith is to cover a spot with a clear cover, heat it with focused sunlight (mirrors), and let the water vapor condense on the cover. Collect the condensate on the edges of the cover. At ground level the Martian atmosphere has a pressure of 6.518 millibars or 0.095 psi as compared to the Earth's sea level atmospheric pressure of 14.7 psi. <ref>Mars. Mars.nasa.gov. (1997). Retrieved 15 November 2021, from https://mars.nasa.gov/MPF/mpf/realtime/mars2.html.</ref> Boiling point of water at 6.518 millibars: 1.5 degC, 34.7 degF. <ref>Water - Boiling Points at Vacuum Pressure. Engineeringtoolbox.com. (2021). Retrieved 15 November 2021, from https://www.engineeringtoolbox.com/water-evacuation-pressure-temperature-d_1686.html.</ref>

"Excavated regolith can be processed by crushing, dry-grinding, and running it through a continuous feed electrically heated rotary kiln, heating to temperatures above 500˚C to decompose perchlorates, <ref>James D. Little (2019). 3: Aeneas Complex: A Plan For A Sustainable, Permanent 1000 Person Settlement On Mars in the book Mars colonies: Plans for Settling the Red Planet (p. 58).</ref><ref>Marvin, G., Woolaver, L., Thermal Decomposition of Perchlorates, Industrial & Engineering Chemistry Analytical Edition, 1945, Vol. 17, Iss. 8, pp. 474-476.</ref><ref>Bruck. A., Sutter, B., Ming, D., Mahaffy, P., Thermal Decomposition of Calcium Perchlorate/Iron-mineral Mixtures: Implications of the Evolved Oxygen from the Rocknest Eolian Deposit in Gale Crater, Mars., 45th Lunar and Planetary Science Conference, Mar. 2014.</ref>
[Ca(H2O)4](ClO4)2 -> Ca(ClO4)2 + 4H2O
oxides, sulfates, carbonates, and nitrates driving off gases and water vapor. The gases are processed through aseries of PSA equipment. The remaining regolith can be sifted and sorted, using various ore processing techniques, such as magnetic separation for iron rich minerals, and sifting to produce aggregate mixtures suitable for producing 3D printed sulfur concrete."

===Polar regions===
The martian polar regions have extensive ice caps as well as ice filled craters, such as the [[Korolev]] crater, that could serve as water sources. As the poles are usually extremely cold, sources closer to the equator would be more useful for future martian settlements. Note that permafrost has been detected at all latitudes, but above 30 degrees latitude, surface ice is found fairly often.

==Uses==

===Drinking water===
The [[human]] metabolism requires a regular intake of fresh water. Pure liquid water is non-existent on Mars but there is abundant frozen water and hydrated minerals. Since getting liquid water for use will require some industrial effort, the [[recycling]] of all excretion would provide advantages in reducing water use. There are two ways: Wastewater can be [[Potable_water_treatment|treated]], which is partially done on the [[ISS]] already. Alternatively, the water can be kept in a nearly natural cycle, using parts of the [[greenhouse]]s for [[biological wastewater treatment]].

The concentration of deuterium in Martian hydrogen and thus in Martian water is between five and thirteen ten-thousandth-parts.<ref>[http://www.sciencemag.org/content/240/4860/1767.abstract abstract in ''Science'']</ref> or about six times the relative abundance on Earth. Still this concentration is far from the 25% of the body's content of hydrogen that would need to be substituted by deuterium before there are any serious health effects. Deuterium is not a cumulative poison. At about one thousandth part of the hydrogen in Martian water, deuterium would be excreted as fast as it is consumed and would not be a health problem.

===Industrial processes===

Many industrial processes considered for a Mars settlement, in particular the production of [[methanol]] and [[methane]] and other hydrocarbons require hydrogen. This can be obtained by [[electrolysis]] or via thermolysis such as the Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2006.05.013</ref> or the Zinc/Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2015.11.049</ref>. In electrolysis or basic thermolysis, [[Oxygen O2]] is produced as a byproduct. In the Zinc/Sulfur/Iodine cycle, CO2 and H2O are inputs and the outputs are CO and H2. CO is industrially useful in the production of [[methanol]] and other [[Hydrocarbon_synthesis|hydrocarbons]], as well as in mineral refining via the [https://en.wikipedia.org/wiki/Mond_process Mond process]. The H2 can also be combined with atmospheric N2 using a [https://en.wikipedia.org/wiki/Haber_process Haber reactor] to produce [[ammonia]].

Most other processes require the use of significant quantities of water as a [[solvent]] for reagents such as [[acid]]s or [[ammonia]] or a a coolant for high temperature systems.

Power sources which rely on heat engines (such as [[nuclear power]]) require a heat sink to provide the heat differential required for the engine to run. Water or Ice make good materials for this heat sink as they are dense and have high thermal mass. The ice of [[korolev|Korolev Crater]] has been suggested as a potential heat sink sufficient to provide for colony scale power generation.

[[Deuterium]] from martian water may provide a source of fusion fuel for future energy production. Note that deuterium is 2.5 times more concentrated on Mars than on Earth, and may form a viable export.

[[Methanol]] and [[methane]] may be used to feed [[Biological_reactors|methanotrophs]] to produce food or other biologically produced industrial materials.

==See Also==

*[[Martian features that are signs of water ice]]
*[[Sublimation]]
*[[Water Infrastructure|Water infrastructure]] and waste water treatment
*"Mars: A Warmer Wetter Planet", by Jeffrey S. Kargel, ISBN 1-85233-568-8. This important book collected the evidence of water on Mars, and put to rest the idea that Mars had always been a dry planet.

==External links==

*[https://www.youtube.com/watch?v=m2ERsEXAq_s Jeffrey Plaut - Subsurface Ice - 21st Annual International Mars Society Convention]

*[http://en.wikipedia.org/wiki/Water Wikipedia page on water]
*[http://mars.jpl.nasa.gov/express/mission/sc_science_marsis02.html Searching for water with the Mars Express MARSIS instrument.]
*[https://en.wikipedia.org/wiki/Water_on_Mars Wikipedia page on water on Mars]

*[https://www.youtube.com/watch?v=RWNXJk0Y01k The Evolution of Water on Mars]
*[https://www.youtube.com/watch?v=QWcdAvFN_q0 James Wray - The Search for Water and Life on Mars (and Beyond) (November 15, 2018)]
*[https://www.youtube.com/watch?v=b4hCWIQsyps Mars: Ancient Water, Present Day Ice]
*[https://www.youtube.com/watch?v=EJk0hS4_gz4 Water on Mars and the Potential for Martian Life]
*[https://www.youtube.com/watch?v=GX9XzRyuYLc Oceans and Life on Mars]

===References===
<references />

Water

2021-11-15T01:23:08Z

Kee.nethery: A process for obtaining water from the Mars atmosphere.

[[Image:GlassOfWater.jpg|thumb|200px|right|A glass is filled with drinking water.]]

'''Water''' is a chemical compound consisting of a single [[oxygen]] atom bonded to two [[hydrogen]] atoms (''chemical symbols:'' H2O). Water is essential to all known forms of life, and its unique properties make it invaluable for most industrial processes. While water in the liquid phase is abundant on [[Earth]], its icy deposits on [[Mars]] make it into a critical resource to be treasured.

==Evidence for water on Mars==

[[Image:388886main_mars_ice_226x170.jpg|thumb|226px|right|A new crater full of melting ice, as seen from the Mars Reconnaissance Orbiter.]]

[[File:PIA15090nirgalvallismariner9.jpg|thumb|226px|left|Nirgal Vallis, as seen by Mariner 9 This is one of the first images to show evidence of past water on Mars.]]

Starting in 2004, the evidence of the presence of water on Mars has been mounting.

===Past liquid water===
Mars shows evidence of extensive liquid water flowing on its surface in the past and it is the focus of many Mars missions to find out how this water has leaked away over the millennia.

The 1996 [[Mars Pathfinder]] mission discovered plentiful evidence that its landing site, [[Ares Vallis]], was once the bottom of a huge valley system eroded by ancient water.

In 2004, the [[Opportunity]] rover discovered geological markers - stratification and cross-bedding - near its landing site which pointed to significant flows of water at some time in Mars' history.<ref>Michael P. Lamb, John P. Grotzinger, John B. Southard, Nicholas J. Tosca, 2012. "Were Aqueous Ripples on Mars Formed by Flowing Brines?", Sedimentary Geology of Mars, John P. Grotzinger, Ralph E. Milliken. <nowiki>https://doi.org/10.2110/pec.12.102.0139</nowiki></ref>

The Mars Express Orbiter used [[Imaging Spectroscopy|imaging spectroscopy]] to detect hydrated minerals in 2005, strong evidence that surface water was once present in large amounts and for a long duration.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #1. Hydrated minerals – evidence of liquid water on Mars. <nowiki>https://sci.esa.int/web/mars-express/-/51821-1-hydrated-minerals-ndash-evidence-of-liquid-water-on-mars</nowiki></ref>

Further support for the historic existence of flowing water comes from the first observations made by NASA's [[Mars Reconnaissance Orbiter]] (launched in 2005) where the High Resolution Imaging Science Experiment (HiRISE) camera spotted small fractures and cracks in the Martian canyon, [[Candor Chasma]]. The cracks analyzed show signs of mineral alteration in the rock exposed - a sign that liquid water once flowed through these sub-surface pipes.

:"''What caught my eye was the bleaching or lack of dark material along the fracture. That is a sign of mineral alteration by fluids that moved through those joints. It reminded me of something I had seen during field studies in Utah, that is light-tone zones, or 'haloes,' on either side of cracks through darker sandstone''" - Dr. Chris Okubo, a geologist at the University of Arizona, Tucson.

Although this is a sign that the liquid water has since disappeared from these cracks and fractures in the canyon rock, it is interesting to find evidence for ancient water in abundance.

===Current water ice===
Today, water on Mars appears to be concentrated in Martian polar ice, suggesting Mars may once have had a warmer climate, slowly cooling as the atmosphere became a more inefficient insulator for the meager heating from the distant Sun.

In 2004 the [[Mars Express]] orbiter detected spectral evidence of water in the south pole's ice cap and the surrounding area, which ruled out the possibility that the southern ice cap consisted of only carbon dioxide ice.<ref>European Space Agency. March 17, 2004. Water at Martian south pole. https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Water_at_Martian_south_pole</ref>

In 2005, [[Mars Express]] located an area of solid water ice near the north pole.

The Phoenix lander confirmed in 2008 that water ice is not limited to the extreme polar regions.<ref>Smith, P., et al. 2009. H2O at the Phoenix Landing Site. Science: 325, 58-61.</ref>

Photos from the [[Mars Reconnaissance Orbiter]] show frozen water just below the Martian surface (see photograph). Surprisingly the location is far away from the poles (43.28 degrees north latitude, 164.22 degrees east longitude), which raises the hope of large amounts of water all over the planet.
<ref>[http://www.nasa.gov/mission_pages/MRO/news/mro20090924.html Mars Reconnaissance Orbiter Sees Ice Exposed by Meteor Impact]</ref>

====Abundance====
[[Image:MARSIS.jpg|thumb|200px|right|A MARSIS map of Mars' south pole ice deposits.]]
On March 15, 2007, [[Mars Express]]' mission control released more news of extensive frozen water discovered at the Martian [[south pole]]. These new and highly accurate measurements predict that if the ice were to be melted, the whole planet would be covered in a liquid layer 11 meters deep.<ref>The European Space Agency. September 1 2019. Mars Express science highlights: #4. Probing the polar regions. <nowiki>https://sci.esa.int/web/mars-express/-/51824-4-probing-the-polar-regions</nowiki></ref> Although it has been known for many years that the poles have an abundance of ice, it has never been measured to this degree of accuracy. The data comes from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) currently mapping the north pole to gain a better understanding of how much frozen water may be contained there. MARSIS can probe over 2 miles below the Martian surface and has found extensive layered deposits of ice.

===Current liquid water===

Future manned exploration on Mars will require a source of water whether it is in the form of ice or sub-surface [[aquifers]]. The [[Mars Express]] orbiter has uncovered some confusing measurements suggesting there may be liquid water accompanying all that ice. MARSIS bounced back data suggesting at least 90% of the layered deposits under the polar cap are indeed supplies of ice, but a thin layer resembling liquid water is also evident. It is hard to understand the existence of liquid water at the extremely low temperatures predicted. Perhaps high pressures or small geological processes may explain these observations. Another orbiter, NASA's Mars Global Surveyor, has also returned some exciting new evidence for the existence of new flows of liquid water on the Martian surface away from the frozen poles. {{science question|What pressures are required to keep water in a liquid phase at temperatures as low as that on the surface of Mars? - [[User:Ioneill|Ioneill]]}}

The [[Mars Global Surveyor]] arrived at the Red Planet on September 11, 1997 and returned a decade of data on the evolution of the planet before it was lost in November 2006 through energy loss. It was Mars' longest operational artificial satellite. The Mars Orbiter Camera (MOC) onboard revealed new deposits possibly carried as sediment by flowing water in two locations in the past 7 years (press release dated December 6, 2006)<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref>. In images taken in August 1999 and September 2006 of the same location ([[Centauri Montes]] Region), a bright deposit measuring several hundred meters long is evident in the 2006 image but not in the 1999 image. A similar feature was observed at a different location from 2001 to 2005 at [[Terra Sirenum]]. It is worth noting that both locations are in equatorial regions, not usually associated with ice or liquid water. This suggests liquid water remains a characteristic of the Mars landscape, if only sporadically. These discoveries have increased the enthusiasm for the search for [[microbes|microbial life]], but the implications for manned exploration are huge. If there are pockets of liquid water just below the surface, Mars may yet be able to provide our future pioneers with natural springs more familiar on Earth.
[[Image:Water_deposit.jpg|thumb|left|200px|Evidence from the [[Mars Global Surveyor]] MOC instrument that spurts of liquid water may sporadically flow on the Martian surface]]
However, surface water on Mars is short-lived. The Martian atmosphere is very thin (a pressure of 7 millibars, <1% that of Earth's thick atmosphere) and cold (an average global temperature of -55°C or -67F), these two factors deny any long-term existence of liquid water. Surface liquid water will quickly freeze and [[sublimation|sublime]] into the atmosphere, bypassing the [[triple point|liquid phase]]. This phase transition for water on Mars is much like the phase transition for liquid carbon dioxide on Earth when it is released from a CO2 fire extinguisher to produce dry ice snow and CO2 gas. The phase transition for H2O on the surface of Mars occurs below the "[[triple point]]" on the phase diagram so the recent observations of sediment on the surface will have been deposited very quickly by short lived "spurts" of water. Just how short-lived these spurts of water are it is unknown, but a significant volume must have created a formidable river to carry sediment several hundred meters.

At times, the humidity of the Martian atmosphere can reach 100% (at Mars' temperature and pressure). If the temperature was high, salty brines could last several minutes on the Martian surface.

Although there may be other explanations for these long "channels" of sediment, such as rock slides or wind-blown [[sand]] features, the appearance of the deposits seem very water-like. Michael Malin of Malin Space Science Systems, a mission scientist for the MOC says, "''The shapes of these deposits are what you would expect to see if the material were carried by flowing water... they have finger-like branches at the downhill end and easily diverted around small obstacles''".<ref>[http://mars.jpl.nasa.gov/mgs/newsroom/20061206a.html NASA Press Release: ''NASA Images Suggest Water Still Flows in Brief Spurts on Mars'']</ref> It is also possible that other liquids such as 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 1,3-propanediol, ethylene glycol and related liquids could be responsible for [[Recent Liquid Flow on Mars|fluid flow features]] on Mars. While such liquids would be relatively more rare than water, the resistance to freezing of such liquids and mixtures of such liquids with water would allow them to cause fluid flow effects where pure liquid water is impossible.

==Water production==
Water production on Mars for settlement use or for exploration uses can take many forms. As a prime [[In-situ resource utilization|In-situ]] resource the presence of water on Mars is one of its main attractions. Further exploration is needed to determine if the water is available in a relatively pure form, or if it will contain salts and other chemical contaminants requiring water treatment.

===Atmosphere===
The Martian [[atmosphere]] contains water vapour (which on occasion can reach 100% humidity). However, it is normally dry and very thin, which makes extracting water slow and energy intensive. With a device similar to an [[atmospheric mining|air dehumidifier]] the production of water should be feasible all over the planet's surface. An [[experimental setup#water out of the atmosphere|experimental setup]] is necessary to find out all about the viability of this approach.

"The University of Washington has designed an in situ resource utilization system to provide water to a life support system in the laboratory module of the NASA Reference Mission to Mars. This system, the Water Vapor Adsorption Reactor (WAVAR), extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular sieve. The zeolite 3A adsorbs the water vapor until nearly saturated and is then heated within a sealed chamber by microwave radiation to drive off the water for collection. The water vapor flows to a condenser where it freezes and is later liquefied for use in the life support system. In the NASA Reference Mission, water, methane, and oxygen are produced for life support and propulsion via the Sabatier/Electrolysis process from seed hydrogen brought from Earth and Martian atmospheric carbon dioxide. In order for the WAVAR system to be compatible with the NASA Reference Mission, its mass must be less than that of the seed hydrogen and cryogenic tanks apportioned for life support in the Sabatier/Electrolysis process. The WAVAR system is designed for atmospheric conditions observed by the Viking missions, which measured an average global atmospheric water vapor concentration of approx. 2 x 10-6kg/cubic meter. WAVAR performance is analyzed taking into consideration hourly and daily fluctuations in Martian ambient temperature and the corresponding effects on zeolite performance." <ref> Sergio Adan-Plaza, Kirsten Carpenter, Laila Elias, Rob Grover, Mark Hilstad, Chris Hoffman, Matt Scheider, & Adam Bruckner. (1998). Extraction of Atmospheric Water on Mars for the Mars Reference Mission. Lpi.usra.edu. Retrieved 15 November 2021, from https://www.lpi.usra.edu/publications/reports/CB-955/washington.pdf.</ref>

===Caves===
Since the discovery of [[caves]] scientists believe in the possibility of water ice on the ground of the caves. Water ice is abundant under the ground at least near the poles, and probably elsewhere too.

===Glaciers===
The [[Mars Reconnaissance Orbiter]] has found evidence of [[glacier|glaciers]] covered in regolith.<ref>http://www.nasa.gov/home/hqnews/2008/nov/HQ_08-304_MRO_BuriedGlaciers.html</ref> Radar reflection data indicates that these are not Rock Glaciers that have been previously suspected on Mars, but instead are thick glacial ice covered in a thin layer of debris. The buried glaciers lie in the [[Hellas Planitia|Hellas Basin]] region of Mars' southern hemisphere with similar aprons detected extending from cliffs in the northern hemisphere.

===Regolith===
Water is present in the martian regolith both as ice and as hydrated minerals. In addition, a recent paper has shown that a huge amount of water has been absorbed by rocks. On Earth, plate Tectonics takes these hydrated minerals and melts them, where water can return to the surface via vulcanism. On Mars the water remains in these minerals. <ref>https://science.sciencemag.org/content/early/2021/03/15/science.abc7717 - Long term drying of Mars by sequestration of Ocean-scale volumes of water in the crust</ref>

===Polar regions===
The martian polar regions have extensive ice caps as well as ice filled craters, such as the [[Korolev]] crater, that could serve as water sources. As the poles are usually extremely cold, sources closer to the equator would be more useful for future martian settlements. Note that permafrost has been detected at all latitudes, but above 30 degrees latitude, surface ice is found fairly often.

==Uses==

===Drinking water===
The [[human]] metabolism requires a regular intake of fresh water. Pure liquid water is non-existent on Mars but there is abundant frozen water and hydrated minerals. Since getting liquid water for use will require some industrial effort, the [[recycling]] of all excretion would provide advantages in reducing water use. There are two ways: Wastewater can be [[Potable_water_treatment|treated]], which is partially done on the [[ISS]] already. Alternatively, the water can be kept in a nearly natural cycle, using parts of the [[greenhouse]]s for [[biological wastewater treatment]].

The concentration of deuterium in Martian hydrogen and thus in Martian water is between five and thirteen ten-thousandth-parts.<ref>[http://www.sciencemag.org/content/240/4860/1767.abstract abstract in ''Science'']</ref> or about six times the relative abundance on Earth. Still this concentration is far from the 25% of the body's content of hydrogen that would need to be substituted by deuterium before there are any serious health effects. Deuterium is not a cumulative poison. At about one thousandth part of the hydrogen in Martian water, deuterium would be excreted as fast as it is consumed and would not be a health problem.

===Industrial processes===

Many industrial processes considered for a Mars settlement, in particular the production of [[methanol]] and [[methane]] and other hydrocarbons require hydrogen. This can be obtained by [[electrolysis]] or via thermolysis such as the Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2006.05.013</ref> or the Zinc/Sulfur/Iodine cycle<ref>https://doi.org/10.1016/j.ijhydene.2015.11.049</ref>. In electrolysis or basic thermolysis, [[Oxygen O2]] is produced as a byproduct. In the Zinc/Sulfur/Iodine cycle, CO2 and H2O are inputs and the outputs are CO and H2. CO is industrially useful in the production of [[methanol]] and other [[Hydrocarbon_synthesis|hydrocarbons]], as well as in mineral refining via the [https://en.wikipedia.org/wiki/Mond_process Mond process]. The H2 can also be combined with atmospheric N2 using a [https://en.wikipedia.org/wiki/Haber_process Haber reactor] to produce [[ammonia]].

Most other processes require the use of significant quantities of water as a [[solvent]] for reagents such as [[acid]]s or [[ammonia]] or a a coolant for high temperature systems.

Power sources which rely on heat engines (such as [[nuclear power]]) require a heat sink to provide the heat differential required for the engine to run. Water or Ice make good materials for this heat sink as they are dense and have high thermal mass. The ice of [[korolev|Korolev Crater]] has been suggested as a potential heat sink sufficient to provide for colony scale power generation.

[[Deuterium]] from martian water may provide a source of fusion fuel for future energy production. Note that deuterium is 2.5 times more concentrated on Mars than on Earth, and may form a viable export.

[[Methanol]] and [[methane]] may be used to feed [[Biological_reactors|methanotrophs]] to produce food or other biologically produced industrial materials.

==See Also==

*[[Martian features that are signs of water ice]]
*[[Sublimation]]
*[[Water Infrastructure|Water infrastructure]] and waste water treatment
*"Mars: A Warmer Wetter Planet", by Jeffrey S. Kargel, ISBN 1-85233-568-8. This important book collected the evidence of water on Mars, and put to rest the idea that Mars had always been a dry planet.

==External links==

*[https://www.youtube.com/watch?v=m2ERsEXAq_s Jeffrey Plaut - Subsurface Ice - 21st Annual International Mars Society Convention]

*[http://en.wikipedia.org/wiki/Water Wikipedia page on water]
*[http://mars.jpl.nasa.gov/express/mission/sc_science_marsis02.html Searching for water with the Mars Express MARSIS instrument.]
*[https://en.wikipedia.org/wiki/Water_on_Mars Wikipedia page on water on Mars]

*[https://www.youtube.com/watch?v=RWNXJk0Y01k The Evolution of Water on Mars]
*[https://www.youtube.com/watch?v=QWcdAvFN_q0 James Wray - The Search for Water and Life on Mars (and Beyond) (November 15, 2018)]
*[https://www.youtube.com/watch?v=b4hCWIQsyps Mars: Ancient Water, Present Day Ice]
*[https://www.youtube.com/watch?v=EJk0hS4_gz4 Water on Mars and the Potential for Martian Life]
*[https://www.youtube.com/watch?v=GX9XzRyuYLc Oceans and Life on Mars]

===References===
<references />

Surface composition

2021-10-18T22:03:25Z

Kee.nethery: /* Overview */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface are primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>jpl.nasa.gov. 2012. Inspecting Soils Across Mars. [online] Available at: <https://www.jpl.nasa.gov/images/inspecting-soils-across-mars> [Accessed 18 October 2021].</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|
|
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Allen, C., Jager, K., Morris, R., Lindstrom, D., Lindstrom, M., & Lockwood, J. (1998). Martian soil stimulant available for scientific, educational study. Eos, Transactions American Geophysical Union, 79(34), 405-405. https://doi.org/10.1029/98eo00309</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Soil

2021-10-18T21:59:46Z

Kee.nethery: /* See also */

[[Image:soilSectional.jpg|thumb|right|200px|soil under grassland - a view into the trench]]

'''Soil''' is the natural medium for [[:category:plants|plants]] to grow in. It provides [[water|moisture]], nutrients and a mechanical foothold. Soil comes into existence in close interaction with living plants and a variety of [[microbes]] and [[insects]]. Since [[Mars]] does not host life, the existence of natural soil is not possible. Soil may play an important part in an [[autonomous colony]] for [[food]] production.

==Why soil?==
A Martian colony may start with a [[greenhouse]] based upon [[hydroponics]], which allows intensive food production right from the beginning. But there are a few advantages in having a small garden with soil, too.

*It can serve as an experimental place for breeding food plants that are not suitable for hydroponics. Later, when bigger greenhouses are built, the garden can be extended to provide a valuable part in the food production. Also, it might be safer to have an alternative production method, as an epidemic plant disease is more likely to occur in a hydroponic monoculture than in a mixed natural plantation.
*It provides some pleasure and has some psychological value. The settlers may want to have a piece of nature for recreation. Although this is terrestrial thinking, the Martian settlers will remain [[human]]s after all.
*It allows other (i.e. more natural) types for water and air recycling, which may require less effort for maintenance. However, this must be a rather big garden to fulfill such tasks.
*A sterile habitat may have a devastating effect on the [[immune system]] of the settlers and their [[children]]. Our physiology was forged in a dirty environment, and there are already theories about the growing number of [[allergy|immune mediated diseases]] in the industrial countries, claiming that the urban living conditions with the low numbers of natural germs put the immune system out of balance.
*Any food production will also produce equal or superior amounts of biomass in the form of branches, stalks and non edible parts. Food itself, once digested and excreted, should be reused as it still contains significant amounts of energy and organised materials, as opposed to the original simple molecules it was made of. Humans eat about one tonne of food per year, so the material required for soil will be created at a minimum rate of one to two tonnes per year per colonist. Using Martian regolith, with a typical [[w:Soil|mineral to biomass ratio]] of 9:1, 10 to 20 tonnes of soil per year could be prepared, per colonist (speculative, need to be checked).
*Hydroponics are fairly complex and can fail dramatically due to infestations, fungi, algae growth and mineral deficiencies. Large amounts of soil may eventually be more stable and secure.

==Composition and structure==
Natural soil contains mineral parts, such as [[sand]] and [[clay]]. Additionally, it contains a variable part of organic matter, such as decomposed pieces of plants and humus. The third part is a complex population of microbes and insects, living in numerous small spaces between the grains and making soil a living system. Soil is also fairly porous, containing about 50% voids, of which 50% is occupied by water. Soil compaction is a significant problem, affecting soil fertility.

==Biological stability==
The living part of the soil is in a constant process of renewal and evolution. It needs energy to carry out the metabolism in every single organism. Many microbes and insects are living in symbiosis with each other and with the plants, growing in the soil. The complexity of soils is not fully understood, and all the requirement are not known. Due to its complexity, the complete functionality of soil cannot be preserved for large periods of time.

From Wikipedia: <nowiki>''</nowiki>Soil is the most abundant ecosystem on Earth, but the vast majority of organisms in soil are microbes, a great many of which have not been described. There may be a population limit of around one billion cells per gram of soil, but estimates of the number of species vary widely from 50,000 per gram to over a million per gram of soil. The total number of organisms and species can vary widely according to soil type, location, and depth<nowiki>''</nowiki>.

Soil contains approximately 2,5 tonnes per hectare of bacteria and other living organisms<ref>https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053862</ref>.

==Artificial soil==
Soil can not be made artificially, but a kind of pre-soil can be made to speed up the development of real soil. In botanical nurseries the pre-soil is a mixture of sand, clay and shredded [[Waste biomass recycling|organic waste]]. It does not contain substantial living parts, such as microbes and insects. The addition of [[compost]] and [[fertilizer]] would be a great enhancement.

After placing the pre-soil in an environment with living plants and natural soil the pre-soil is transformed to natural soil by immigration of microbes, insects and plant roots. The pre-soil provides a good structure and nutrients for those immigrants.

In a young Martian colony there is a lack of organic waste, making it hard to make a good pre-soil mixture. None or very little organic matter can be added to the mineral part. Under these conditions the production of soil takes a long period of time. [[Pioneer plants]] can help to accelerate the process. However, over time as as the population grows, both plants and colonists can contribute larger and larger amounts of organic matter to the soil.

Since soil is complex and not fully understood, in particular its very complex biome, entirely artificial soil does not exist. However, it should be possible to bring from the Earth significative 'seed' soils, that can serve to colonise and enrich artificial soils.

==Open issues==

*How long can soil be held alive in a dark container (e.g. for transportation)?
*What temperature range is required to keep soil alive?
*What species (microbes and insects) are necessary for a functioning symbiosis with plants?
*How long does it take to develop soil from pre-soil (under Martian conditions with regolith as the mineral part)? An [[Experimental setup#soil production|experiment should be carried out]].

== See also ==
* [[Surface composition]]

== References ==
[[Category:Biospherics]]
<references />

Soil

2021-10-18T21:59:10Z

Kee.nethery: add See also.

[[Image:soilSectional.jpg|thumb|right|200px|soil under grassland - a view into the trench]]

'''Soil''' is the natural medium for [[:category:plants|plants]] to grow in. It provides [[water|moisture]], nutrients and a mechanical foothold. Soil comes into existence in close interaction with living plants and a variety of [[microbes]] and [[insects]]. Since [[Mars]] does not host life, the existence of natural soil is not possible. Soil may play an important part in an [[autonomous colony]] for [[food]] production.

==Why soil?==
A Martian colony may start with a [[greenhouse]] based upon [[hydroponics]], which allows intensive food production right from the beginning. But there are a few advantages in having a small garden with soil, too.

*It can serve as an experimental place for breeding food plants that are not suitable for hydroponics. Later, when bigger greenhouses are built, the garden can be extended to provide a valuable part in the food production. Also, it might be safer to have an alternative production method, as an epidemic plant disease is more likely to occur in a hydroponic monoculture than in a mixed natural plantation.
*It provides some pleasure and has some psychological value. The settlers may want to have a piece of nature for recreation. Although this is terrestrial thinking, the Martian settlers will remain [[human]]s after all.
*It allows other (i.e. more natural) types for water and air recycling, which may require less effort for maintenance. However, this must be a rather big garden to fulfill such tasks.
*A sterile habitat may have a devastating effect on the [[immune system]] of the settlers and their [[children]]. Our physiology was forged in a dirty environment, and there are already theories about the growing number of [[allergy|immune mediated diseases]] in the industrial countries, claiming that the urban living conditions with the low numbers of natural germs put the immune system out of balance.
*Any food production will also produce equal or superior amounts of biomass in the form of branches, stalks and non edible parts. Food itself, once digested and excreted, should be reused as it still contains significant amounts of energy and organised materials, as opposed to the original simple molecules it was made of. Humans eat about one tonne of food per year, so the material required for soil will be created at a minimum rate of one to two tonnes per year per colonist. Using Martian regolith, with a typical [[w:Soil|mineral to biomass ratio]] of 9:1, 10 to 20 tonnes of soil per year could be prepared, per colonist (speculative, need to be checked).
*Hydroponics are fairly complex and can fail dramatically due to infestations, fungi, algae growth and mineral deficiencies. Large amounts of soil may eventually be more stable and secure.

==Composition and structure==
Natural soil contains mineral parts, such as [[sand]] and [[clay]]. Additionally, it contains a variable part of organic matter, such as decomposed pieces of plants and humus. The third part is a complex population of microbes and insects, living in numerous small spaces between the grains and making soil a living system. Soil is also fairly porous, containing about 50% voids, of which 50% is occupied by water. Soil compaction is a significant problem, affecting soil fertility.

==Biological stability==
The living part of the soil is in a constant process of renewal and evolution. It needs energy to carry out the metabolism in every single organism. Many microbes and insects are living in symbiosis with each other and with the plants, growing in the soil. The complexity of soils is not fully understood, and all the requirement are not known. Due to its complexity, the complete functionality of soil cannot be preserved for large periods of time.

From Wikipedia: <nowiki>''</nowiki>Soil is the most abundant ecosystem on Earth, but the vast majority of organisms in soil are microbes, a great many of which have not been described. There may be a population limit of around one billion cells per gram of soil, but estimates of the number of species vary widely from 50,000 per gram to over a million per gram of soil. The total number of organisms and species can vary widely according to soil type, location, and depth<nowiki>''</nowiki>.

Soil contains approximately 2,5 tonnes per hectare of bacteria and other living organisms<ref>https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053862</ref>.

==Artificial soil==
Soil can not be made artificially, but a kind of pre-soil can be made to speed up the development of real soil. In botanical nurseries the pre-soil is a mixture of sand, clay and shredded [[Waste biomass recycling|organic waste]]. It does not contain substantial living parts, such as microbes and insects. The addition of [[compost]] and [[fertilizer]] would be a great enhancement.

After placing the pre-soil in an environment with living plants and natural soil the pre-soil is transformed to natural soil by immigration of microbes, insects and plant roots. The pre-soil provides a good structure and nutrients for those immigrants.

In a young Martian colony there is a lack of organic waste, making it hard to make a good pre-soil mixture. None or very little organic matter can be added to the mineral part. Under these conditions the production of soil takes a long period of time. [[Pioneer plants]] can help to accelerate the process. However, over time as as the population grows, both plants and colonists can contribute larger and larger amounts of organic matter to the soil.

Since soil is complex and not fully understood, in particular its very complex biome, entirely artificial soil does not exist. However, it should be possible to bring from the Earth significative 'seed' soils, that can serve to colonise and enrich artificial soils.

==Open issues==

*How long can soil be held alive in a dark container (e.g. for transportation)?
*What temperature range is required to keep soil alive?
*What species (microbes and insects) are necessary for a functioning symbiosis with plants?
*How long does it take to develop soil from pre-soil (under Martian conditions with regolith as the mineral part)? An [[Experimental setup#soil production|experiment should be carried out]].

== See also ==
{{div col|colwidth=30em}}
* [[Surface composition]]
{{Div col end}}

== References ==
[[Category:Biospherics]]
<references />

Surface composition

2021-10-18T21:05:39Z

Kee.nethery: /* Viking Lander 1 & 2, Pathfinder, JSC Martian Soil SimulantCarlton C. Allen, Karen M. Jager, Richard V. Morris, David J. Lindstrom, Marilyn M. Lindstrom, John P. Lockwood, Martian Soil Simulant Available for Scientific, Educational Study, (EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION), Volume 79, Number 34, August 25 1998, pages 405-409, Table 1. */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface is primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>jpl.nasa.gov. 2012. Inspecting Soils Across Mars. [online] Available at: <https://www.jpl.nasa.gov/images/inspecting-soils-across-mars> [Accessed 18 October 2021].</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|
|
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Allen, C., Jager, K., Morris, R., Lindstrom, D., Lindstrom, M., & Lockwood, J. (1998). Martian soil stimulant available for scientific, educational study. Eos, Transactions American Geophysical Union, 79(34), 405-405. https://doi.org/10.1029/98eo00309</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Surface composition

2021-10-18T21:01:32Z

Kee.nethery: /* Spirit, Opportunity, Curiosity Rovershttps://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012 */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface is primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>jpl.nasa.gov. 2012. Inspecting Soils Across Mars. [online] Available at: <https://www.jpl.nasa.gov/images/inspecting-soils-across-mars> [Accessed 18 October 2021].</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|
|
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Carlton C. Allen, Karen M. Jager, Richard V. Morris, David J. Lindstrom, Marilyn M. Lindstrom, John P. Lockwood, ''Martian Soil Simulant Available for Scientific, Educational Study'', (EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION), Volume 79, Number 34, August 25 1998, pages 405-409, Table 1.</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Surface composition

2021-10-18T01:40:17Z

Kee.nethery: /* Spirit, Opportunity, Curiosity Rovershttps://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012 */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface is primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>https://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|
|
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Carlton C. Allen, Karen M. Jager, Richard V. Morris, David J. Lindstrom, Marilyn M. Lindstrom, John P. Lockwood, ''Martian Soil Simulant Available for Scientific, Educational Study'', (EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION), Volume 79, Number 34, August 25 1998, pages 405-409, Table 1.</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Surface composition

2021-10-18T01:38:58Z

Kee.nethery: /* Spirit, Opportunity, Curiosity Rovershttps://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012 */

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface is primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>https://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit data taken from 59 samples at Gusev Crater, Opportunity data taken from 23 samples at Meridiani Planum, Curiosity data taken from a sample inside a rover wheel scuff at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

[[File:Jpl nasa gov jpegPIA16572.width-1280.jpg]]
Note: In the image SiO2 and FeO values were divided by 10 to not overrun the boundaries of the image, and Ni, Zn, and Br were multiplied by 100 to be visible.

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Carlton C. Allen, Karen M. Jager, Richard V. Morris, David J. Lindstrom, Marilyn M. Lindstrom, John P. Lockwood, ''Martian Soil Simulant Available for Scientific, Educational Study'', (EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION), Volume 79, Number 34, August 25 1998, pages 405-409, Table 1.</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

File:Jpl nasa gov jpegPIA16572.width-1280.jpg

2021-10-18T01:30:10Z

Kee.nethery: Image from ppl.nasa.gov report https://www.jpl.nasa.gov/images/inspecting-soils-across-mars Note: SiO2 and FeO numbers displayed have been divided by 10 so they'll fit on the chart, and Ni, Zn, and Br numbers have been multiplied by 100 to show up on the chart. The Spirit and Opportunity deviation bars show the deviations in the various samples that were taken. Only one sample was taken with Curiosity.

== Summary ==
Image from ppl.nasa.gov report https://www.jpl.nasa.gov/images/inspecting-soils-across-mars
Note: SiO2 and FeO numbers displayed have been divided by 10 so they'll fit on the chart, and Ni, Zn, and Br numbers have been multiplied by 100 to show up on the chart. The Spirit and Opportunity deviation bars show the deviations in the various samples that were taken. Only one sample was taken with Curiosity.
== Licensing ==
{{PD}}

Surface composition

2021-10-18T01:24:44Z

Kee.nethery: Added materials from Spirit, Opportunity, and Curiosity

{{Stub}}
==Overview==
A predominant feature of the [[Mars|Martian]] surface is the [[iron|iron oxide]]-rich dust known as [[regolith]], giving the planet its characteristic red color. This dust is very fine and the result of years of [[meteorites|meteorite]] impacts pulverizing the Martian surface spreading dust around the planet. This dust is blown globally by storms, creating massive seasonal [[dust storms]] that can last for months.

Rock formations on the surface is primarily composed of basalt - a consequence of the extensive lava flows that once existed as a result of ancient geological activity. Analysis of soil samples collected by the [[GFDL:Viking_1|Viking landers]] in 1976 indicate iron-rich clays consistent with weathering of basaltic rocks.

[[Image:Erebus_360.jpg|thumb|right|400px|Panorama taken on the rim of Erebus crater]]
There is also evidence the Martian surface may be more silica-rich than the basalt created by lava flows, similar to [[exd:andesitic|andesitic]] rocks found on [[Earth]] (rock which crystallizes from silicate minerals at intermediate temperatures).

Mars has twice as much iron oxide in its outer layers as Earth does, despite their similar origin (meteorite impacts). This is due to the geologically active (and hotter) Earth transporting much of the surface iron deep below the terrestrial surface. Mars does not have this geological advantage to produce heat, so the iron remains in the Martian regolith, giving Mars its red glow.

==Materials==
Chemical composition of the soils on Mars is based upon the various data we have to date from Mars landers as well as SNC-meteorites believed to be from Mars. Different sites and sources contain different concentrations.

===Spirit, Opportunity, Curiosity Rovers<ref>https://www.jpl.nasa.gov/images/inspecting-soils-across-mars Dec 3 2012</ref>===
Values estimated from a graph. Measurements provided by their Alpha Particle X-ray Spectrometer (APXS). Spirit of 59 samples at Gusev Crater, Opportunity of 23 samples at Meridiani Planum, Curiosity of inside a wheel scuff sample at Gale Crater.

{|
|
|
|Spirit    
|Opportunity  
|Curiosity
|-
|SiO2
|Silicon Dioxide
|46.0
|45.3
|43.6
|-
|FeO
|Iron(II) Oxide
|16.0
|18.8
|21.3
|-
|Al2O3
|Aluminum Oxide
|10.2
|9.16
|9.58
|-
|MgO
|Magnesium Oxide
|8.61
|7.39
|6.55
|-
|CaO
|Calcium Oxide
|6.27
|6.93
|7.39
|-
|SO3
|Sulfur Trioxide
|6.13
|5.92
|5.16
|-
|Na2O
|Sodium Oxide
|3.00
|2.20
|2.20
|-
|P2O5
|Phosphorus Pentoxide  
|0.91
|0.84
|0.56
|-
|TiO2
|Titanium Dioxide
|0.91
|1.05
|1.53
|-
|Cl
|Chlorine
|0.70
|0.64
|0.63
|-
|K2O
|Potassium Oxide
|0.42
|0.49
|0.63
|-
|Cr2O3  
|Chromium(III) Oxide
|0.35
|0.42
|0.42
|-
|MnO
|Manganese(II) Oxide
|0.28
|0.35
|0.42
|-
|Ni
|Nickel
|0.047
|0.045
|0.035
|-
|Zn
|Zinc
|0.027
|0.033
|0.027
|-
|Br
|Bromine
|0.005
|0.008
|0.003
|}

===Viking Lander 1 & 2, Pathfinder, JSC Martian Soil Simulant<ref>Carlton C. Allen, Karen M. Jager, Richard V. Morris, David J. Lindstrom, Marilyn M. Lindstrom, John P. Lockwood, ''Martian Soil Simulant Available for Scientific, Educational Study'', (EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION), Volume 79, Number 34, August 25 1998, pages 405-409, Table 1.</ref>===
JSC Mars-1 is a simulated Martian soil developed for use in: scientific research, engineering studies, and education.

{|
|
|Viking 1  
|Viking 2  
|Pathfinder  
|JSC Mars-1 volatiles  
|JSC Mars-1 dry
|-
|Oxide
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|(Wt%)
|-
|SiO2
|43
|43
|44.0
|34.5
|43.5
|-
|Al2O3
|7.3
|7
|7.5
|18.5
|23.3
|-
|TiO2
|0.66
|0.56
|1.1
|3.0
|3.8
|-
|Fe2O3
|18.5
|17.8
|16.5
|12.4
|15.6
|-
|MnO
|n.a.
|n.a.
|n.a.
|0.2
|0.3
|-
|CaO
|5.9
|5.7
|5.6
|4.9
|6.2
|-
|MgO
|6
|6
|7.0
|2.7
|3.4
|-
|K2O
|<0.15
|<0.15
|0.3
|0.5
|0.6
|-
|Na2O
|n.a.
|n.a.
|2.1
|1.9
|2.4
|-
|P2O5
|n.a.
|n.a.
|n.a.
|0.7
|0.9
|-
|SO3
|6.6
|8.1
|4.9
|n.a.
|n.a.
|-
|Cl
|0.7
|0.5
|0.5
|n.a.
|n.a.
|-
|Volatiles  
|n.a.
|n.a.
|n.a.
|21.8
|n.a.
|-
|Total
|89
|89
|89.5
|101.1
|100.0
|}

n.a. = Not Analyzed: all iron calculated as Fe2O3

===SNC-meteorites<ref>P. Cattermole, ''Mars: The story of the Red Planet'', (Springer Science & Business Media, Dec 6, 2012 - Science), page 51, Table 5.1.</ref>===
SNC Meteorites are meteorites ejected from Mars and named SNC after the locations where they were first discovered.

{|
|Mantle Crust
|Name
|(%)
|-
|SiO2
|Silicon Dioxide
|44.4
|-
|Al2O3
|Aluminum Oxide
|3.02
|-
|FeO
|Iron(II) Oxide
|17.9
|-
|MgO
|Magnesium Oxide
|30.2
|-
|CaO
|Calcium Oxide
|2.45
|-
|TiO2
|Titanium Dioxide
|0.14
|-
|Na2O
|Sodium Oxide
|0.50
|-
|P2O5
|Phosphorus Pentoxide
|0.16
|-
|Cr2O3
|Chromium(III) Oxide
|0.76
|-
|K
|Potassium
|305ppm
|-
|Ni
|Nickel
|400ppm
|}

[[category:Mineralogy]]

==Notes==
<references />

Surface composition

2021-10-18T00:22:02Z

Kee.nethery: /* Materials */

Surface composition

2021-10-18T00:13:47Z

Kee.nethery: Added tables of the various materials assumed to be present on the Mars surface.