Jump to content

Terraforming of Mars

Page protected with pending changes
From Wikipedia, the free encyclopedia

This article is about the technological process. For the board game, seeTerraforming Mars (board game).

A series of four illustrations of a planet, each successive one featuring more liquid water, vegetation, clouds, and atmospheric haze
Artist's conception of the process of terraformingMars

Theterraforming of Marsor theterraformation of Marsis a hypothetical procedure that would consist of aplanetary engineeringproject or concurrent projects aspiring to transformMarsfrom a planet hostile toterrestrial lifeto one that could sustainablyhost humansand other lifeforms free of protection or mediation. The process would involve the modification of the planet's extantclimate,atmosphere,and surface through a variety of resource-intensive initiatives, as well as the installation of a novelecological systemor systems.

Justifications for choosing Mars over other potential terraforming targets include the presence of water and a geological history that suggests it once harbored a dense atmosphere similar to Earth's. Hazards and difficulties include low gravity, toxic soil, low light levels relative to Earth's, and the lack of amagnetic field.

Disagreement exists about whether current technology could render the planet habitable. Reasons for objecting to terraforming includeethical concerns about terraformingand the considerable cost that such an undertaking would involve. Reasons for terraforming the planet include allaying concerns about resource use and depletion on Earth and arguments that the altering and subsequent or concurrent settlement of other planets decreases the odds ofhumanity's extinction.

Motivation and side effects[edit]

See also:Ethics of terraforming
Illustration of plants growing in a hypothetical Mars base[1]

Future population growth, demand for resources, and an alternate solution to theDoomsday argumentmay require human colonization ofbodiesother thanEarth,such asMars,theMoon,and other objects.Space colonizationwould facilitate harvesting theSolar System's energy and material resources.[2]

In many aspects, Mars is the most Earth-like of all the other planets in the Solar System.[citation needed]It is thought[3]that Mars had a more Earth-like environment early in itsgeological history,with a thickeratmosphereand abundant water that was lost over the course of hundreds of millions of years throughatmospheric escape.Given the foundations of similarity and proximity, Mars would make one of the most plausible terraforming targets in the Solar System.

Side effects of terraforming include the potential displacement or destruction of anyindigenous lifeif such life exists.[4][5][6][7]

Challenges and limitations[edit]

See also:Colonization of Mars
This diagram shows the change in theatmosphere escapingfrom Mars if it was close to the average temperature on Earth. Mars is thought to have been warm in the past (due to evidence of liquid water on the surface) and terraforming would make it warm again. At these temperatures oxygen and nitrogen would escape into space much faster than they do today.

The Martian environment presents several terraforming challenges to overcome and the extent of terraforming may be limited by certain key environmental factors. The process of terraforming aims to mitigate the following distinctions between Mars and Earth, among others:

  • Reduced light levels (about 60% of Earth)[8]
  • Low surface gravity (38% of Earth's)
  • Unbreathable atmosphere[9]
  • Low atmospheric pressure (about 1% of Earth's; well below theArmstrong limit)
  • Ionizing solar andcosmic radiationat the surface[10]
  • Average temperature −63 °C (210 K; −81 °F) compared to Earth average of 14 °C (287 K; 57 °F))[11]
  • Molecular instability - bonds between atoms break down in critical molecules such asorganic compounds
  • Global dust storms
  • No natural food source[12]
  • Toxic soil[13][14]
  • No global magnetic field to shield against thesolar wind

Countering the effects of space weather[edit]

See also:Health threat from cosmic rays

Mars doesn't have an intrinsic global magnetic field, but thesolar winddirectly interacts with the atmosphere of Mars, leading to the formation of a magnetosphere frommagnetic field tubes.[15]This poses challenges for mitigatingsolar radiationand retaining an atmosphere.

The lack of a magnetic field, its relatively small mass, and its atmospheric photochemistry, all would have contributed to the evaporation and loss of its surface liquid water over time.[16]Solar wind–induced ejection of Martian atmospheric atoms has been detected by Mars-orbiting probes, indicating that the solar wind has stripped the Martian atmosphere over time. For comparison, while Venus has a dense atmosphere, it has only traces of water vapor (20 ppm) as it lacks a large, dipole-induced, magnetic field.[15][17][16] Earth'sozone layerprovides additional protection. Ultraviolet light is blocked before it can dissociate water into hydrogen and oxygen.[18]

Low gravity and pressure[edit]

Thesurface gravityon Mars is 38% of that on Earth. It is not known if this is enough to prevent the health problems associated withweightlessness.[19]

Mars'sCO
2atmosphere has about 1% the pressure of the Earth's at sea level. It is estimated that there is sufficientCO
2ice in theregolithand the south polar cap to form a 30 to 60kilopascals[kPa] (4.4 to 8.7 psi) atmosphere if it is released by planetary warming.[20]The reappearance of liquid water on the Martian surface would add to the warming effects and atmospheric density,[20]but the lowergravity of Marsrequires 2.6 times Earth's column airmass to obtain the optimum 100 kPa (15 psi) pressure at the surface.[21]Additional volatiles to increase the atmosphere's density must be supplied from an external source, such as redirecting several massive asteroids (40-400 billion tonnes total) containingammonia(NH
3) as a source ofnitrogen.[20]

Breathing on Mars[edit]

Current conditions in the Martian atmosphere, at less than 1 kPa (0.15 psi) of atmospheric pressure, are significantly below theArmstrong limitof 6 kPa (0.87 psi) where very low pressure causes exposed bodily liquids such as saliva, tears, and the liquids wetting the alveoli within the lungs to boil away. Without apressure suit,no amount of breathableoxygendelivered by any means will sustain oxygen-breathing life for more than a few minutes.[22][23]In theNASAtechnical reportRapid (Explosive) Decompression Emergencies in Pressure-Suited Subjects,after exposure to pressure below the Armstrong limit, a survivor reported that his "last conscious memory was of the water on histonguebeginning to boil ".[23]In these conditions humans die within minutes unless a pressure suit provides life support.

If Mars' atmospheric pressure could rise above 19 kPa (2.8 psi), then a pressure suit would not be required. Visitors would only need to wear a mask that supplied 100% oxygen under positive pressure. A further increase to 24 kPa (3.5 psi) of atmospheric pressure would allow a simple mask supplying pure oxygen.[24][clarification needed]This might look similar to mountain climbers who venture into pressures below 37 kPa (5.4 psi), also called thedeath zone,where an insufficient amount of bottled oxygen has often resulted inhypoxiawith fatalities.[25]However, if the increase in atmospheric pressure was achieved by increasing CO2(or other toxic gas) the mask would have to ensure the external atmosphere did not enter the breathing apparatus. CO2concentrations as low as 1% cause drowsiness in humans. Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen. (SeeCarbon dioxide toxicity.)

In 2021, the NASA Mars rover Perseverance was able to make oxygen on Mars. However, the process is complex and takes a considerable amount of time to produce a small amount of oxygen.[26]

Advantages[edit]

See also:Atmosphere of Mars
Hypothetical terraformed Mars

According to scientists, Mars exists on the outer edge of thehabitable zone,a region of the Solar System where liquid water on the surface may be supported if concentrated greenhouse gases could increase the atmospheric pressure.[20]The lack of both amagnetic fieldand geologic activity on Mars may be a result of its relatively small size, which allowed the interior to cool more quickly than Earth's, although the details of such a process are still not well understood.[27][28]

There are strong indications that Mars once had an atmosphere as thick as Earth's during an earlier stage in its development, and that its pressure supported abundant liquidwater at the surface.[29]Although water appears to have once been present on the Martian surface, ground ice currently exists from mid-latitudes to the poles.[30][31]Thesoilandatmosphere of Marscontain many of the main elements crucial to life, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon.[32]

Any climate change induced in the near term is likely to be driven by greenhouse warming produced by an increase in atmosphericcarbon dioxide(CO
2) and a consequent increase in atmospheric water vapor. These two gases are the only likely sources of greenhouse warming that are available in large quantities in Mars' environment.[33]Large amounts ofwater iceexist below the Martian surface, as well as on the surface at the poles, where it is mixed withdry ice,frozen CO2.Significant amounts of water are located at the south pole of Mars, which, if melted, would correspond to a planetwide ocean 5–11 meters deep.[34][35]Frozencarbon dioxide(CO2) at the polessublimesinto the atmosphere during the Martian summers, and small amounts of water residue are left behind, which fast winds sweep off the poles at speeds approaching 400 km/h (250 mph).[citation needed][original research?]This seasonal occurrence transports large amounts ofdustandwater iceinto the atmosphere, forming Earth-likeiceclouds.[36]

Most of the oxygen in the Martian atmosphere is present as carbon dioxide (CO2), the main atmospheric component. Molecularoxygen(O2) only exists in trace amounts. Large amounts of oxygen can be also found inmetal oxideson the Martian surface, and in the soil, in the form ofper-nitrates.[37]An analysis of soil samples taken by thePhoenix landerindicated the presence ofperchlorate,which has been used to liberate oxygen inchemical oxygen generators.[38]Electrolysiscould be employed to separate water on Mars into oxygen andhydrogenif sufficient liquid water and electricity were available. However, if vented into the atmosphere it would escape into space.

Proposed methods and strategies[edit]

See also:Oxygen evolution
Comparison of dry atmosphere
Atmospheric
property 		Mars Earth
Pressure 0.61 kPa (0.088 psi) 101.3 kPa (14.69 psi)
Carbon dioxide(CO2) 96.0% 0.04%
Argon(Ar) 2.1% 0.93%
Nitrogen(N2) 1.9% 78.08%
Oxygen(O2) 0.145% 20.94%

Terraforming Mars would entail three major interlaced changes: building up the magnetosphere, building up the atmosphere, and raising the temperature. The atmosphere of Mars is relatively thin and has a very low surface pressure. Because its atmosphere consists mainly of CO2,a knowngreenhouse gas,once Mars begins to heat, the CO2may help to keepthermal energynear the surface. Moreover, as it heats, more CO2should enter the atmosphere from the frozen reserves on the poles, enhancing thegreenhouse effect.This means that the two processes of building the atmosphere and heating it would augment each other, favoring terraforming. However, it would be difficult to keep the atmosphere together because of the lack of a protective global magnetic field against erosion by thesolar wind.[39][40][41][42]

Importing ammonia[edit]

One method of augmenting the Martian atmosphere is to introduceammonia(NH3). Large amounts of ammonia are likely to exist in frozen form on minor planets orbiting in theouter Solar System.It might be possible to redirect the orbits of these or smaller ammonia-rich objects so that they collide with Mars, thereby transferring the ammonia into the Martian atmosphere.[43][20]Ammonia is not stable in the Martian atmosphere, however. It breaks down into (diatomic) nitrogen and hydrogen after a few hours.[44]Thus, though ammonia is a powerfulgreenhouse gas,it is unlikely to generate much planetary warming. Presumably, the nitrogen gas would eventually be depleted by the same processes that stripped Mars of much of its original atmosphere, but these processes are thought to have required hundreds of millions of years. Being much lighter, the hydrogen would be removed much more quickly. Carbon dioxide is 2.5 times the density of ammonia, and nitrogen gas, which Mars barely holds on to, is more than 1.5 times the density, so any imported ammonia that did not break down would also be lost quickly into space.

Importing hydrocarbons[edit]

Another way to create a Martian atmosphere would be to importmethane(CH4) or otherhydrocarbons,[45][46]which are common inTitan'satmosphere and on itssurface;the methane could be vented into the atmosphere where it would act to compound the greenhouse effect.[47]However, like ammonia (NH3), methane (CH4) is a relatively light gas. It is in fact even less dense than ammonia and so would similarly be lost into space if it was introduced, and at a faster rate than ammonia. Even if a method could be found to prevent it escaping into space, methane can exist in the Martian atmosphere for only a limited period before it is destroyed. Estimates of its lifetime range from 0.6–4 years.[48][49]

Use of fluorine compounds[edit]

Especially powerful greenhouse gases, such assulfur hexafluoride,chlorofluorocarbons(CFCs), orperfluorocarbons(PFCs), have been suggested both as a means of initially warming Mars and of maintaining long-term climate stability.[20][21][50][33]These gases are proposed for introduction because they generate a greenhouse effect thousands of times stronger than that of CO2.Fluorine-based compounds such as sulphur hexafluoride and perfluorocarbons are preferable to chlorine-based ones as the latter destroysozone.It has been estimated that approximately 0.3 microbars of CFCs would need to be introduced into Mars' atmosphere to sublimate the south polar CO2glaciers.[50]This is equivalent to a mass of approximately 39 million tonnes, that is, about three times the amount of CFCs manufactured on Earth from 1972 to 1992 (when CFC production was banned by international treaty).[50]Maintaining the temperature would require continual production of such compounds as they are destroyed due to photolysis. It has been estimated that introducing 170 kilotons of optimal greenhouse compounds (CF3CF2CF3,CF3SCF2CF3,SF6,SF5CF3,SF4(CF3)2) annually would be sufficient to maintain a 70-K greenhouse effect given a terraformed atmosphere with earth-like pressure and composition.[21]

Typical proposals envision producing the gases on Mars using locally extracted materials, nuclear power, and a significant industrial effort. The potential for mining fluorine-containing minerals to obtain the raw material necessary for the production of CFCs and PFCs is supported by mineralogical surveys of Mars that estimate the elemental presence of fluorine in the bulk composition of Mars at 32 ppm by mass (as compared to 19.4 ppm for the Earth).[21]

Alternatively, CFCs might be introduced by sending rockets with payloads of compressed CFCs on collision courses with Mars.[37]When the rockets crashed into the surface they would release their payloads into the atmosphere. A steady barrage of these "CFC rockets" would need to be sustained for a little over a decade while Mars changed chemically and became warmer.

Use of orbital mirrors[edit]

Mirrors made of thin aluminizedPET filmcould be placed in orbit around Mars to increase the totalinsolationit receives.[20]This would direct the sunlight onto the surface and could increase Mars's surface temperature directly. The 125 km radius mirror could be positioned as astatite,using its effectiveness as asolar sailto orbit in a stationary position relative to Mars, near the poles, to sublimate theCO
2ice sheet and contribute to the warming greenhouse effect. However, certain problems have been found with this. The main concern is the difficulty of launching large mirrors from Earth.[20]

Albedo reduction[edit]

Reducing thealbedoof the Martian surface would also make more efficient use of incoming sunlight in terms of heat absorption.[51]This could be done by spreading dark dust from Mars's moons,PhobosandDeimos,which are among the blackest bodies in the Solar System; or by introducing darkextremophilemicrobial life forms such aslichens,algaeand bacteria.[citation needed]The ground would then absorb more sunlight, warming the atmosphere. However, Mars is already the second-darkest planet in the solar system, absorbing over 70% of incoming sunlight so the scope for darkening it further is small.

If algae or other green life were established, it would also contribute a small amount ofoxygento the atmosphere, though not enough to allow humans to breathe. The conversion process to produce oxygen is highly reliant upon water, without which the CO2is mostly converted to carbohydrates.[52]In addition, because on Mars atmospheric oxygen is lost into space (unless an artificial magnetosphere were to be created; see "Protecting the atmosphere" below), such life would need to be cultivated inside a closed system.

On April 26, 2012, scientists reported thatlichensurvived and showed remarkable results on the adaptation capacity of photosynthetic activity within the simulation time of 34 days underMartian conditionsin the Mars Simulation Laboratory (MSL) maintained by theGerman Aerospace Center(DLR).[53][54]

One final issue with albedo reduction is the commonMartian dust storms.These cover the entire planet for weeks, and not only increase the albedo, but block sunlight from reaching the surface. This has been observed to cause a surface temperature drop which the planet takes months to recover from.[55]Once the dust settles it then covers whatever it lands on, effectively erasing the albedo reduction material from the view of theSun.

Funded research: ecopoiesis[edit]

The Mars Ecopoiesis Test Bed showing its transparent dome to allow for solar heat and photosynthesis, and the cork-screw system to collect and sealMartian soiltogether with oxygen-producing Earth organisms. Total length is about 7 centimetres (2.8 in).

Since 2014, theNASA Institute for Advanced Concepts(NIAC) program and Techshot Inc have been working together to develop sealed biodomes that would employ colonies of oxygen-producingcyanobacteriaandalgaefor the production of molecular oxygen (O2) on Martian soil.[56][57][58]But first they need to test if it works on a small scale on Mars.[59]The proposal is called Mars Ecopoiesis Test Bed.[60]Eugene Boland is the Chief Scientist at Techshot, a company located in Greenville, Indiana.[56]They intend to send small canisters ofextremophilephotosyntheticalgaeandcyanobacteriaaboard a future rover mission. The rover would cork-screw the 7 cm (2.8 in) canisters into selected sites likely to experience transients of liquid water, drawing someMartian soiland then release oxygen-producing microorganisms to grow within the sealed soil.[56][61]The hardware would use Martian subsurface ice as its phase changes into liquid water.[59]The system would then look for oxygen given off asmetabolic byproductand report results to a Mars-orbiting relay satellite.[58][61]

If this experiment works on Mars, they will propose to build several large and sealed structures calledbiodomes,to produce and harvest oxygen for a futurehuman mission to Marslife support systems.[61][62]Being able to create oxygen there would provide considerable cost-savings to NASA and allow for longer human visits to Mars than would be possible if astronauts have to transport their own heavy oxygen tanks.[62]This biological process, calledecopoiesis,would be isolated, in contained areas, and is not meant as a type of globalplanetary engineeringfor terraforming of Mars's atmosphere,[58][62]but NASA states that "This will be the first major leap from laboratory studies into the implementation of experimental (as opposed to analytical) planetaryin situresearch of greatest interest to planetary biology, ecopoiesis, and terraforming. "[58]

Research at theUniversity of Arkansaspresented in June 2015 suggested that somemethanogenscould survive inMars's low pressure.[63]Rebecca Mickol found that in her laboratory, four species of methanogens survived low-pressure conditions that were similar to a subsurface liquidaquiferon Mars. The four species that she tested wereMethanothermobacterwolfeii,Methanosarcinabarkeri,Methanobacteriumformicicum,andMethanococcus maripaludis.[63]Methanogens do not require oxygen or organic nutrients, are non-photosynthetic, use hydrogen as their energy source and carbon dioxide (CO2) as their carbon source, so they could exist in subsurface environments on Mars.[63]

Protecting the atmosphere[edit]

Escaping atmosphereon Mars (carbon,oxygen,andhydrogen) byMAVENinUV[64]

One key aspect of terraforming Mars is to protect the atmosphere (both present and future-built) from being lost into space. Some scientists hypothesize that creating a planet-wide artificial magnetosphere would be helpful in resolving this issue. According to two NIFS Japanese scientists, it is feasible to do that with current technology by building a system of refrigerated latitudinal superconducting rings, each carrying a sufficient amount ofdirect current.[65]

In the same report, it is claimed that the economic impact of the system can be minimized by using it also as a planetary energy transfer and storage system (SMES).

Magnetic shield at L1orbit[edit]

Magnetic shield on L1 orbit around Mars

During the Planetary Science Vision 2050 Workshop[16]in late February 2017, NASA scientist Jim Green proposed a concept of placing amagnetic dipolefield between the planet and the Sun to protect it from high-energy solar particles. It would be located at the MarsLagrange orbit L1at about 320 R♂,creating a partial and distant artificial magnetosphere. The field would need to be "Earth comparable" and sustain50 μTas measured at 1 Earth-radius. The paper abstract cites that this could be achieved by a magnet with a strength of 1–2teslas(10,000–20,000gauss).[66]If constructed, the shield may allow the planet to partially restore its atmosphere.[67][68][16]

Plasma torus along the orbit of Phobos[edit]

A plasma torus along the orbit of Phobos by ionizing and accelerating particles from the moon may be sufficient to create a magnetic field strong enough to protect a terraformed Mars.[69][70]

Thermodynamics of terraforming[edit]

The overall energy required to sublimate the CO2from the south polar ice cap was modeled by Zubrin and McKay in 1993.[20]If using orbital mirrors, an estimated 120MW-yearsof electrical energy would be required to produce mirrors large enough to vaporize the ice caps. This is considered the most effective method, though the least practical. If using powerful halocarbon greenhouse gases, an order of 1,000 MW-years of electrical energy would be required to accomplish this heating. However, if all of this CO2were put into the atmosphere, it would only double[33]the current atmospheric pressure from 6 mbar to 12 mbar, amounting to about 1.2% of Earth's mean sea level pressure. The amount of warming that could be produced today by putting even 100 mbar of CO2into the atmosphere is small, roughly of order10 K.[33]Additionally, once in the atmosphere, it likely would be removed quickly, either by diffusion into the subsurface andadsorptionor by re-condensing onto the polar caps.[33]

The surface or atmospheric temperature required to allow liquid water to exist has not been determined, and liquid water conceivably could exist when atmospheric temperatures are as low as 245 K (−28 °C; −19 °F). However, a warming of10 Kis much less than thought necessary to produce liquid water.[33]

See also[edit]

References[edit]

  1. ^Keeter, Bill (February 6, 2018)."ISS Daily Summary Report – 2/06/2018".NASA.Archivedfrom the original on January 19, 2022.RetrievedMay 26,2019.
  2. ^Savage, Marshall Thomas (1992).The Millennial Project: Colonizing the Galaxy in Eight Easy Steps.Little, Brown and Company.ISBN978-0-316-77163-4.Archivedfrom the original on July 2, 2019.RetrievedApril 19,2018.
  3. ^Wall, Mike (April 8, 2013)."Most of Mars' Atmosphere Is Lost in Space".Space.Archivedfrom the original on January 30, 2016.RetrievedApril 9,2013.
  4. ^"Bungie's Destiny and the Science of Terraforming – Critical Intel – The Escapist".The Escapist.September 11, 2014.Archivedfrom the original on September 24, 2015.RetrievedJune 2,2015.
  5. ^Fogg, Martyn J. (October 1999).The Ethical Dimensions of Space Settlement(PDF).50th International Astronautical Congress. Amsterdam, The Netherlands:International Astronautical Federation.IAA-99-IAA.7.1.07.Archived(PDF)from the original on September 23, 2017.
  6. ^"The ethics of terraforming Mars: a review"(PDF).iGEM Valencia Team. 2010. Archived fromthe original(PDF)on December 5, 2019.RetrievedMay 26,2019.
  7. ^McKay, Christopher (2002). "Do Indigenous Martian Bacteria have Precedence over Human Exploration?". In Zubrin, Robert (ed.).On to Mars: Colonizing a New World.Apogee Books Space Series. pp. 177–182.ISBN1-896522-90-4.
  8. ^"Sunlight on Mars – Is There Enough Light on Mars to Grow Tomatoes?".first the seed foundation.Archivedfrom the original on November 26, 2018.RetrievedNovember 26,2018.
  9. ^Franz, Heather B.; Trainer, Melissa G.; Malespin, Charles A.; Mahaffy, Paul R.; Atreya, Sushil K.; Becker, Richard H.; Benna, Mehdi; Conrad, Pamela G.; Eigenbrode, Jennifer L. (April 1, 2017). "Initial SAM calibration gas experiments on Mars: Quadrupole mass spectrometer results and implications".Planetary and Space Science.138:44–54.Bibcode:2017P&SS..138...44F.doi:10.1016/j.pss.2017.01.014.ISSN0032-0633.
  10. ^Gifford, Sheyna E. (February 18, 2014)."Calculated Risks: How Radiation Rules Manned Mars Exploration".Space.Archivedfrom the original on December 10, 2019.RetrievedNovember 26,2018.
  11. ^"Focus Sections:: The Planet Mars".MarsNews. Archived from the original on April 7, 2015.RetrievedSeptember 8,2007.{{cite web}}:CS1 maint: unfit URL (link)
  12. ^Scoles, Sarah (November 27, 2023)."Mars Needs Insects - If humans are ever going to live on the red planet, they're going to have to bring bugs with them".The New York Times.Archivedfrom the original on November 28, 2023.RetrievedNovember 28,2023.
  13. ^Sample, Ian (July 6, 2017)."Mars covered in toxic chemicals that can wipe out living organisms, tests reveal".The Guardian.Archivedfrom the original on February 18, 2021.RetrievedNovember 26,2018.
  14. ^David, Leonard (June 13, 2013)."Toxic Mars: Astronauts Must Deal with Perchlorate on the Red Planet".Space.Archivedfrom the original on November 20, 2020.RetrievedNovember 26,2018.
  15. ^abVaisberg, O. L.; Ermakov, V. N.; Shuvalov, S. D.; Zelenyi, L. M.; Halekas, J.; DiBraccio, G. A.; McFadden, J.; Dubinin, E. M. (March 23, 2018)."The Structure of Martian Magnetosphere at the Dayside Terminator Region as Observed on MAVEN Spacecraft".Journal of Geophysical Research:Space Physics.123(4).American Geophysical Union(published April 2018): 2679–2695.arXiv:1801.08878.doi:10.1002/2018JA025202.eISSN2169-9402.ISSN2169-9380.Archivedfrom the original on September 7, 2021.
  16. ^abcdGreen, J.L.; Hollingsworth, J.A Future Mars Environment for Science and Exploration(PDF).Planetary Science Vision 2050 Workshop 2017.Archived(PDF)from the original on October 1, 2021.RetrievedAugust 4,2020.
  17. ^Svedhem, Hakan; Titov, Dmitry V.; Taylor, Fredric W.; Witasse, Oliver (November 29, 2007). "Venus as a more Earth-like planet".Nature.450(7170): 629–632.Bibcode:2007Natur.450..629S.doi:10.1038/nature06432.PMID18046393.S2CID1242297.
  18. ^Garner, Rob (September 30, 2015)."How to Protect Astronauts from Space Radiation on Mars".NASA.Archivedfrom the original on March 6, 2016.RetrievedMarch 3,2016.
  19. ^Gravity Hurts (so Good)ArchivedMay 28, 2017, at theWayback Machine– NASA 2001
  20. ^abcdefghiRobert M. Zubrin (Pioneer Astronautics), Christopher P. McKay.NASA Ames Research Center(c. 1993)."Technological Requirements for Terraforming Mars".Archivedfrom the original on February 1, 2016.RetrievedAugust 10,2006.
  21. ^abcdGerstell, M. F.; Francisco, J. S.; Yung, Y. L.; Boxe, C.; Aaltonee, E. T. (2001)."Keeping Mars warm with new super greenhouse gases".Proceedings of the National Academy of Sciences.98(5): 2154–2157.Bibcode:2001PNAS...98.2154G.doi:10.1073/pnas.051511598.PMC30108.PMID11226208.
  22. ^Geoffrey A. Landis."Human Exposure to Vacuum".Geoffrey A. Landis.Archivedfrom the original on July 21, 2009.RetrievedMarch 21,2016.
  23. ^ab"Human Body in a Vacuum".Archived fromthe originalon October 14, 2014.
  24. ^"NASA – Airborne Science – ER-2 History of the Pressure Suit".Archived fromthe originalon March 25, 2016.RetrievedMarch 22,2016.
  25. ^Grocott, Michael P.W.; Martin, Daniel S.; Levett, Denny Z.H.; McMorrow, Roger; Windsor, Jeremy; Montgomery, Hugh E. (2009)."Arterial Blood Gases and Oxygen Content in Climbers on Mount Everest".N Engl J Med.360(2): 140–9.doi:10.1056/NEJMoa0801581.PMID19129527.Archivedfrom the original on October 1, 2021.RetrievedSeptember 22,2021.
  26. ^"NASA's Perseverance rover produces oxygen on Mars in historic first — water could be next, scientists say".April 22, 2021.
  27. ^Valentine, Theresa; Amde, Lishan (November 9, 2006)."Magnetic Fields and Mars".Mars Global Surveyor @ NASA.Archivedfrom the original on September 14, 2012.RetrievedJuly 17,2009.
  28. ^"Multiple Asteroid Strikes May Have Killed Mars's Magnetic Field – WIRED".WIRED.January 20, 2011.Archivedfrom the original on June 26, 2015.RetrievedJune 2,2015.
  29. ^Dr. Tony Phillips (November 21, 2008)."Solar Wind Rips Up Martian Atmosphere".NASA. Archived fromthe originalon February 17, 2009.RetrievedApril 1,2015.
  30. ^Steep Slopes on Mars Reveal Structure of Buried IceArchivedJune 17, 2019, at theWayback Machine.NASA Press Release. January 11, 2018.
  31. ^Ice cliffs spotted on MarsArchivedJanuary 28, 2018, at theWayback Machine.Science News.Paul Voosen. January 11, 2018.
  32. ^Dwayne Brown (March 12, 2013)."NASA Rover Finds Conditions Once Suited for Ancient Life on Mars".Jet Propulsion Laboratory.Archivedfrom the original on January 5, 2019.RetrievedSeptember 2,2014.
  33. ^abcdefCan Mars be Terraformed?ArchivedSeptember 6, 2017, at theWayback Machine(PDF) B. M. Jakosky and C. S. Edwards. Lunar and Planetary Science XLVIII, 2017
  34. ^R.C. (March 2007)."Radar Probes Frozen Water at Martian Pole".Science News.171(13): 206.doi:10.1002/scin.2007.5591711315.JSTOR20055502.Archivedfrom the original on November 1, 2012.RetrievedSeptember 9,2012.(subscription required)
  35. ^"Water on Mars: Exploration & Evidence".Space.October 7, 2015.Archivedfrom the original on May 12, 2016.RetrievedMay 8,2016.
  36. ^"Water Clouds on Mars".Archivedfrom the original on June 2, 2016.RetrievedAugust 1,2014.
  37. ^abLovelock, James; Allaby, James (1984).The Greening of Mars.St. Martin's Press.ISBN9780312350246.
  38. ^Hecht; et al. (2009)."Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site".Science.325(5936). Science Magazine: 64–7.Bibcode:2009Sci...325...64H.doi:10.1126/science.1172466.PMID19574385.S2CID24299495.Archivedfrom the original on July 18, 2014.RetrievedJanuary 13,2014.
  39. ^Chang, Kenneth (November 5, 2015)."Solar Storms Strip Air From Mars, NASA Says".The New York Times.Archivedfrom the original on August 25, 2019.RetrievedNovember 5,2015.
  40. ^Staff (November 5, 2015)."VIDEO (51:58) – MAVEN – Measuring Mars' Atmospheric Loss".NASA.Archivedfrom the original on August 25, 2017.RetrievedNovember 5,2015.
  41. ^Northon, Karen (November 5, 2015)."NASA Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere".NASA.Archivedfrom the original on January 12, 2019.RetrievedNovember 5,2015.
  42. ^Wall, Mike (November 5, 2015)."Mars Lost Atmosphere to Space as Life Took Hold on Earth".Space.Archivedfrom the original on July 18, 2018.RetrievedNovember 6,2015.
  43. ^Dandridge M. Cole;Donald William Cox (1964).Islands in Space: The Challenge of the Planetoids.Chilton Books. pp. 126–127.
  44. ^Whitehouse, David (July 15, 2004)."Dr. David Whitehouse – Ammonia on Mars could mean life".BBC News.Archivedfrom the original on October 31, 2012.RetrievedAugust 14,2012.
  45. ^Mat Conway (February 27, 2007)."Now We're There: Terraforming Mars".Aboutmyplanet. Archived fromthe originalon July 23, 2011.RetrievedAugust 20,2011.
  46. ^"Terraforming – Can we create a habitable planet?"(PDF).Archived(PDF)from the original on April 20, 2018.RetrievedJanuary 16,2010.
  47. ^"Overview of Greenhouse Gases".epa.gov.United States Government EPA. December 23, 2015.Archivedfrom the original on August 12, 2016.RetrievedOctober 24,2016.
  48. ^Mumma, Michael J.; et al. (February 20, 2009)."Strong Release of Methane on Mars in Northern Summer 2003"(PDF).Science.323(5917): 1041–1045.Bibcode:2009Sci...323.1041M.doi:10.1126/science.1165243.PMID19150811.S2CID25083438.RetrievedNovember 26,2018.
  49. ^Franck, Lefèvre; Forget, François (August 6, 2009). "Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics".Nature.460(7256): 720–723.Bibcode:2009Natur.460..720L.doi:10.1038/nature08228.PMID19661912.S2CID4355576.
  50. ^abcTeles, A. M. M. (2015). Jin, Shuanggen; Haghighipour, Nader;Ip, Wing-Huen(eds.). "Mars Astrobiology: Recent Status and Progress".Planetary Exploration and Science: Recent Results and Advances:147–245.doi:10.1007/978-3-662-45052-9.ISBN978-3-662-45051-2.S2CID125651936.
  51. ^Peter Ahrens."The Terraformation of Worlds"(PDF).Nexial Quest. Archived fromthe original(PDF)on June 9, 2019.RetrievedOctober 18,2007.
  52. ^"Plants Don't Convert CO2 into O2" How Plants Work ".How Plants Work.February 16, 2009.Archivedfrom the original on August 22, 2015.RetrievedJune 2,2015.
  53. ^Baldwin, Emily (April 26, 2012)."Lichen survives harsh Mars environment".Skymania.Archivedfrom the original on May 28, 2012.RetrievedApril 27,2012.
  54. ^de Vera, J.-P.; Kohler, Ulrich (April 26, 2012)."The adaptation potential of extremophiles to Martian surface conditions and its implication for the habitability of Mars"(PDF).European Geosciences Union.Archived fromthe original(PDF)on May 4, 2012.RetrievedApril 27,2012.
  55. ^Fenton, Lori K.; Geissler, Paul E.; Haberle, Robert M. (2007)."Global warming and climate forcing by recent albedo changes on Mars"(PDF).Nature.446(7136): 646–649.Bibcode:2007Natur.446..646F.doi:10.1038/nature05718.PMID17410170.S2CID4411643.Archived fromthe original(PDF)on July 8, 2007.
  56. ^abcWentz, Rachel K. (May 16, 2015)."NASA Hopes to Rely on Algae and Bacteria for Oxygen Production on Mars".The Science Times.Archivedfrom the original on May 19, 2015.RetrievedMay 17,2015.
  57. ^Wall, Mike (June 6, 2014)."NASA Funds 12 Futuristic Space Tech Concepts".Space.Archivedfrom the original on May 19, 2015.RetrievedMay 17,2015.
  58. ^abcd"NIAC 2014 Phase 1 Selections".NASA Innovative Advanced Concepts (NIAC).June 5, 2014.Archivedfrom the original on March 30, 2015.RetrievedMay 18,2015.
  59. ^abDavid, Leonard."Terraforming in a Bottle on Mars".Aerospace America Magazine.Archivedfrom the original on January 28, 2016.RetrievedMay 17,2015.Page 8
  60. ^Mars ecopoiesis test bed: on Earth and on the Red PlanetArchivedJuly 4, 2017, at theWayback Machine.Todd, Paul; Kurk, Michael Andy; Boland, Eugene; Thomas, David; Scherzer, Christopher. Abstract for the 41st COSPAR Scientific Assembly. August 23, 2017
  61. ^abcBurnham, R. (June 6, 2014)."Mars 'terraforming' test among NAIC proposals".The Red Planet Report.Archivedfrom the original on May 20, 2015.RetrievedMay 17,2015.
  62. ^abcBeach, Justin (May 17, 2015)."NASA's plan to use bacteria to produce oxygen on Mars".National Monitor.Archivedfrom the original on May 20, 2015.RetrievedMay 17,2015.
  63. ^abc"Earth organisms survive under low-pressure Martian conditions".University of Arkansas.June 2, 2015.Archivedfrom the original on June 4, 2015.RetrievedJune 4,2015.
  64. ^Jones, Nancy; Steigerwald, Bill; Brown, Dwayne; Webster, Guy (October 14, 2014)."NASA Mission Provides Its First Look at Martian Upper Atmosphere".NASA.Archivedfrom the original on October 19, 2014.RetrievedOctober 15,2014.
  65. ^Motojima, Osamu; Yanagi, Nagato (May 2008)."Feasibility of Artificial Geomagnetic Field Generation by a Superconducting Ring Network"(PDF).National Institute for Fusion Science (Japan).Archived(PDF)from the original on September 10, 2016.RetrievedJune 7,2016.
  66. ^"Policy, Pathways, Techniques, and Capabilities – from NASA Planetary Science: Vision 2050 (Talk: A Future Mars Environment for Science and Exploration)".Archivedfrom the original on March 14, 2017.RetrievedMarch 13,2017.: 1:36:00 
  67. ^Beall, Abigail (March 6, 2017)."NASA wants to put a giant magnetic shield around Mars so humans can live there".Wired.Archivedfrom the original on September 13, 2017.RetrievedSeptember 15,2017.
  68. ^Bennett, Jay (March 1, 2017)."NASA Considers Magnetic Shield to Help Mars Grow Its Atmosphere".Popular Mechanics.Archivedfrom the original on March 14, 2017.RetrievedMarch 13,2017.
  69. ^Bamford, R.A.; Kellett, B.J.; Green, J.L.; Dong, C.; Airapetian, V.; Bingham, R. (2022)."How to create an artificial magnetosphere for Mars".Acta Astronautica.190:323–333.arXiv:2111.06887.doi:10.1016/j.actaastro.2021.09.023.
  70. ^Koberlein, Brian (November 19, 2021)."An Absolutely Bonkers Plan to Give Mars an Artificial Magnetosphere".Universe Today.RetrievedNovember 22,2021.

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Terraforming_of_Mars&oldid=1235087207"