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== Habitability ==
Chemical, physical, geological, and geographic attributes shape the environments on Mars. Isolated measurements of these factors may be insufficient to deem an environment habitable, but the sum of measurements can help predict locations with greater or lesser habitability potential.<ref name="2013 LPS">{{cite journal |bibcode=2013LPICo1719.2185C |title=Habitability Assessment at Gale Crater: Implications from Initial Results |last=Conrad |first=P. G. |last2=Archer |first2=D. |last3=Coll |first3=P. |last4=De La Torre |first4=M. |last5=Edgett |first5=K. |last6=Eigenbrode |first6=J. L. |last7=Fisk |first7=M. |last8=Freissenet |first8=C. |last9=Franz |first9=H. |last10=Glavin |first10=D. P. |last11=Gómez |first11=F. |last12=Haberle |first12=R. |last13=Hamilton |first13=V. |last14=Jones |first14=J. H. |last15=Kah |first15=L. C. |last16=Leshin |first16=L. A. |last17=Mahaffy |first17=P. M. |last18=McAdam |first18=A. |last19=McKay |first19=C. P. |last20=Navarro-González |first20=R. |last21=Steele |first21=A. |last22=Stern |first22=J. |last23=Sumner |first23=D. |last24=Treiman |first24=A. H. |last25=Wong |first25=M. H. |last26=Wray |first26=J. |last27=Yingst |first27=R. A. |author28=MSL Science Team |display-authors=9 |volume=1719 |date=2013 |pages=2185 |journal=44th Lunar and Planetary Science Conference }}</ref> The main factors needed for life are water availability, temperature, presence of nutrients, an energy source, and protection from Solar ultraviolet. For dormant life then protection from [[Cosmic ray|galactic cosmic radiation]] and solar storms is needed, but this is not a significant factor for non dormant extant life.
The soil geochemistry of Mars is favourable for life with Schueger concluding<ref name="D.C.Golden">{{cite journal |bibcode=2012P&SS...72...91S |title=Biotoxicity of Mars soils: 1. Dry deposition of analog soils on microbial colonies and survival under Martian conditions |url=https://www.researchgate.net/profile/Andrew_Schuerger/publication/233854615_Biotoxicity_of_Mars_Soils_1_Dry_Deposition_of_Analog_Soils_on_Microbial_Colonies_and_Survival_under_Martian_Conditions/links/5a8f3314a6fdccecffffda5d/Biotoxicity-of-Mars-Soils-1-Dry-Deposition-of-Analog-Soils-on-Microbial-Colonies-and-Survival-under-Martian-Conditions.pdf |last=Schuerger |first=Andrew C. |last2=Golden |first2=D. C. |last3=Ming |first3=Doug W. |volume=72 |issue=1 |date=2012 |pages=91–101 |journal=Planetary and Space Science |doi=10.1016/j.pss.2012.07.026}}</ref><ref name="Beaty">{{cite journal |bibcode=2006AsBio...6..677M |title=Findings of the Mars Special Regions Science Analysis Group | author1=MEPAG Special Regions-Science Analysis Group | last2=Beaty | first2=D. | last3=Buxbaum | first3=K. | last4=Meyer | first4=M. | last5=Barlow | first5=N. | last6=Boynton | first6=W. | last7=Clark | first7=B. | last8=Deming | first8=J. | last9=Doran | first9=P. T. | last10=Edgett | first10=K. | last11=Hancock | first11=S. | last12=Head | first12=J. | last13=Hecht | first13=M. | last14=Hipkin | first14=V. | last15=Kieft | first15=T. | last16=Mancinelli | first16=R. | last17=McDonald | first17=E. | last18=McKay | first18=C. | last19=Mellon | first19=M. | last20=Newsom | first20=H. | last21=Ori | first21=G. | last22=Paige | first22=D. | last23=Schuerger | first23=A. C. | last24=Sogin | first24=M. | last25=Spry | first25=J. A. | last26=Steele | first26=A. | last27=Tanaka | first27=K. | last28=Voytek | first28=M. | display-authors=9 | volume=6 | date=2006 | pages=677–732 | journal=Astrobiology | doi=10.1089/ast.2006.6.677 | pmid=17067257 | issue=5 }}</ref>:
{{quote|Results suggest that Mars soils are likely not to be overtly biotoxic to terrestrial microorganisms, and suggest that the soil geochemistries on Mars will not preclude the habitability of the Martian surface.}}
Scientists do not know the minimum number of parameters for determination of habitability potential, but they are certain it is greater than one or two of the factors in the table below.<ref name="2013 LPS" /> Similarly, for each group of parameters, the habitability threshold for each is to be determined.<ref name="2013 LPS" /> Laboratory simulations show that whenever multiple lethal factors are combined, the survival rates plummet quickly.<ref name="dust-up">{{cite web|url=http://www.astrobio.net/exclusive/3495/mars-contamination-dust-up |title=Mars Contamination Dust-Up |first=Charles |last=Q. Choi, |date=May 17, 2010 |publisher=Astrobiology Magazine |quote=Whenever multiple biocidal factors are combined, the survival rates plummet quickly, |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20110820212814/http://www.astrobio.net/exclusive/3495/mars-contamination-dust-up |archivedate=August 20, 2011 |df= }}</ref> There are no full-Mars simulations published yet that include all of the biocidal factors combined.<ref name="dust-up" />
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