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[[File:Viking Oven.jpg|thumb|right|300px|<center>A Viking lander being prepared for [[dry heat sterilization]]{{snd}} this remains the "Gold standard"<ref>[http://solarsystem.nasa.gov/docs/PPCCTECHREPORT3.pdf Assessment of
The Viking spacecraft were heat=treated for 30 hours at 112 °C, nominal 125 °C (five hours at 112 °C was considered enough to reduce the population tenfold even for enclosed parts of the spacecraft, so this was enough for a million-fold reduction of the originally low population).<ref name=JPL2011/>
</center>NASA's introduction to planetary protection:
<youtube width="300" height="150">fnX_FGKENx8</youtube>
First video on [https://planetaryprotection.nasa.gov/overview overview page of the NASA Office of Planetary Protection]
]]
'''Planetary protection''' is a guiding principle in the design of
https://www.wired.com/wiredscience/2013/10/spraying-bugs-on-mars-1964 |date=2 October 2013 |work=[[Wired (magazine)|Wired]] |accessdate=3 October 2013 }}</ref>
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Its recommendations depend on the type of space mission and the celestial body explored.<ref name="COSPAR PLANETARY PROTECTION POLICY">[https://web.archive.org/web/20130306111646/https://science.nasa.gov/media/medialibrary/2012/05/04/COSPAR_Planetary_Protection_Policy_v3-24-11.pdf COSPAR PLANETARY PROTECTION POLICY] (20 October 2002; As Amended to 24 March 2011)</ref> COSPAR categorizes the missions into 5 groups:
*''Category I:'' Any mission to locations not of direct interest for chemical evolution or the [[Abiogenesis|origin of life]], such as the [[Sun]] or [[Mercury (planet)|Mercury]]. No planetary protection requirements.<ref name="OPPaboutcategories"
<!-- no longer exists [http://planetaryprotection.nasa.gov/about-categories/ Office of Planetary Protection - About The Categories] -->
[https://cosparhq.cnes.fr/sites/default/files/pppolicydecember_2017.pdf COSPAR’s Planetary Protection Policy (as of 2017)]
</ref>
*''Category II:'' Any mission to locations of significant interest for chemical evolution and the origin of life, but only a remote chance that spacecraft-borne contamination could compromise investigations. Examples include the [[Moon]], [[Venus]], and [[comet]]s. Requires simple documentation only, primarily to outline intended or potential impact targets, and an end of mission report of any inadvertent impact site if such occurred.<ref name="OPPaboutcategories" />
*''Category III:'' Flyby and orbiter missions to locations of significant interest for chemical evolution or the origin of life, and with a significant chance that contamination could compromise investigations e.g., [[Mars]], [[Europa (moon)|Europa]], [[Enceladus (moon)|Enceladus]]. Requires more involved documentation than Category II. Other requirements, depending on the mission, may include trajectory biasing, clean room assembly, bioburden reduction, and if impact is a possibility, inventory of organics.<ref name="OPPaboutcategories" />
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:: '''Missions to Mars in category IV are subclassified further:'''<ref name="COSPAR PLANETARY PROTECTION POLICY"/>
:*''Category IVa.'' Landers that do not search for Martian life - uses the Viking lander pre-sterilization requirements, a maximum of 300,000 spores per spacecraft and 300 spores per square meter.
:*''Category IVb.'' Landers that search for Martian life. Either the complete lander or the life detection systems must be sterilized to at least to the Viking post-sterilization biological burden levels of 30 spores total per spacecraft. If only the subsystem that acquires and analyses the samples is sterilized in this way, then there needs to be a method to prevent recontamination of the sterilized systems or the samples [an example here might be a drill that can drill down to a potential habitat for present day life]
:*''Category IVc.'' Any component that accesses a Martian ''[[#Mars special regions|special region]]'' where terrestrial organisms are likely to propagate, or interpreted to have a high potential for existence of extamt Martian life forms.<ref name=MarsSpecialRegions2014/> (see [[#Mars special regions |below]]) must be sterilized to at least to the Viking post-sterilization biological burden levels of 30 spores total per spacecraft.
*''Category V:'' This is further divided into unrestricted and restricted sample return.
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For restricted Category V missions, the current recommendation<ref name=ESFsection12>[http://www.esf.org/fileadmin/Public_documents/Publications/MarsSampleReturn.pdf Mars Sample Return backward contamination – Strategic advice and requirements] {{webarchive|url=https://web.archive.org/web/20130819141409/http://www.esf.org/fileadmin/Public_documents/Publications/MarsSampleReturn.pdf |date=2013-08-19 }}- foreword and section 1.2</ref> is that no uncontained samples should be returned unless sterilized. Since sterilization of the returned samples would destroy much of their science value, current proposals involve containment and quarantine procedures. For details, see [[#Containment and quarantine for restricted Category V sample return|Containment and quarantine]] below. Category V missions also have to fulfill the requirements of Category IV to protect the target body from forward contamination.
(COSPAR,2020, COSPAR Policy on Planetary Protection : 2)
===Category I===
{{quotation|“not of direct interest for understanding the process of chemical evolution or the origin of life.” <ref name=PlanetaryProtectionCategories>{{cite web|title=
NASA’s Planetary Protection policy calls for the imposition of controls on contamination for certain combinations of mission type and target body. There are five categories for target body/mission type combinations. The assignment of categories for specific missions is made by the NASA Planetary Protection Officer based on multidisciplinary scientific advice. The five categories are
* Category I includes any mission to a target body, which is not of direct interest for understanding the process of chemical evolution or the origin of life. No protection of such bodies is warranted and no Planetary Protection requirements are imposed.
* Category II includes all types of missions to those target bodies where there is significant interest relative to the process of chemical evolution and the origin of life, but where there is only a remote chance that contamination carried by a spacecraft could jeopardize future exploration. The requirements are only for simple documentation. This documentation includes a short Planetary Protection plan, which is required for these missions, primarily to outline intended or potential impact targets; brief pre-launch and post-launch analyses detailing impact strategies; and a post-encounter and end-of-mission report providing the location of inadvertent impact, if such an event occurs.
* Category III includes certain types of missions (typically a flyby or orbiter) to a target body of chemical evolution or origin-of-life interest or for which scientific opinion holds that the mission would present a significant chance of contamination which could jeopardize future biological exploration. Requirements consist of documentation (more involved than that for Category II) and some implementing procedures, including trajectory biasing, the use of clean rooms (Class 100,000 or better) during spacecraft assembly and testing and possibly bioburden reduction. Although no impact is generally intended for Category III missions, an inventory of bulk constituent organics is required if the probability of inadvertent impact is significant.
* Category IV includes certain types of missions (typically an entry probe, lander or rover) to a target body of chemical evolution or origin-of-life interest or for which scientific opinion holds that the mission would present a significant chance of contamination, which could jeopardize future biological exploration. Requirements include rather detailed documentation (more involved than that for Category III), bioassays to enumerate the burden, a probability of contamination analysis, an inventory of the bulk constituent organics and an increased number of implementing procedures. The latter may include trajectory biasing, the use of clean rooms (Class 100,000 or better) during spacecraft assembly and testing, bioload reduction, possible partial sterilization of the hardware having direct contact with the taget body, and a bioshield for that hardware, and, in rare cases, a complete sterilization of the entire spacecraft. Subdivisions of Category IV (designated IVa, IVb or IVc) address lander and rover missions to Mars (with or without life detection experiments) and missions landing or accessing regions on Mars, which are of particularly high biological interest.
Category V pertains to all missions for which the spacecraft, or a spacecraft component, returns to Earth. The concern for these missions is the protection of the Earth from back contamination resulting from the return of extraterrestrial samples (usually soil and rocks). A subcategory called "Unrestricted Earth Return" is defined for solar system bodies deemed by scientific opinion to have no indigenous life forms. Missions in this subcategory have requirements on the outbound (Earth to target body) phase only, corresponding to the category of that phase (typically Category I or II).
For all other Category V missions, in a subcategory defined as "Restricted Earth Return," the highest degree of concern is expressed by requiring the absolute prohibition of destructive impact upon return; the need for containment throughout the return phase of all returning hardware, which directly contacted the target body or unsterilized material from the body; and the need for containment of any unsterilized samples collected and returned to Earth. Post-mission, there is a need to conduct timely analyses of the returned unsterilized samples, under strict containment, and using the most sensitive techniques. If any sign of the existence of a nonterrestrial replicating organism is found, the returned sample must remain contained unless treated by an effective sterilization procedure. Category V concerns are reflected in requirements that encompass those of Category IV plus a continuous monitoring of mission activities, studies, and research in sterilization procedures and containment techniques.
}}</ref>}}
* Io, Sun, Mercury, undifferentiated metamorphosed asteroids
===Category II===
{{quotation|… where there is significant interest relative to the process of chemical evolution and the origin of life, but where there is only a remote<sup>1</sup> chance that contamination carried by a spacecraft could compromise future investigations.
1: “Remote” here implies the absence of environments where terrestrial organisms could survive and replicate, or a very low likelihood of transfer to environments where terrestrial organisms could survive and replicate.
<ref name=smallsolarsystembodies/><ref name=PlanetaryProtectionCategories/><ref name="PlanetaryProtectionCategories2020">{{cite web |last=COSPAR|title=COSPAR Policy on Planetary Protection |url=
https://hal.science/hal-03017948/document |date=2020}}</ref>}}
* Callisto, comets, asteroids of category P, D, and C, Venus,<ref>[http://www.nap.edu/openbook.php?record_id=11584 Assessment of Planetary Protection Requirements for Venus Missions -- Letter Report]</ref> Kuiper belt objects (KBO) < 1/2 size of Pluto.
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===Category III / IV===
These are category III for orbiters and category IV for landers.
{{quotation|“…where there is a significant chance that contamination carried by a spacecraft could jeopardize future exploration.” We define “significant chance” as “the presence of niches (places where terrestrial microorganisms could proliferate) and the likelihood of transfer to those places.” <ref name=smallsolarsystembodies/><ref name=PlanetaryProtectionCategories/>}}
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==Mars special regions==
A ''special region'' on Mars is a region classified by COSPAR where terrestrial organisms are likely to propagate, or interpreted to have a high potential for existence of
(A special region is considered to be "... a region within which terrestrial organisms are likely to propagate, or a region which is interpreted to have a high potential for the existence of extant Martian life forms. Given current understanding, this applies to regions where liquid water is present or may occur." (Reference: COSPAR 2002 & 2005, NASA, 2005))"''}}</ref>. Based on current understanding, this includes any region with a high enough temperature for Earth organisms to propagate (above -18°C), and with water in a form accessible to them (water activity higher than 0.6) {{refn|name=special_region_def|(see section 7.1.1. Recommended organism-based parameters defin-ing the limits of life, and the requirements for Mars Special Regions, page 940 of<ref name=MarsSpecialRegions2014/>)
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}}, both requirements to be satisfied simultaneously.
Other environmental factors such as the perchlorates and other chemistry {{refn|name=perchlorates|(see section 2.1, page 891 of<ref name=MarsSpecialRegions2014/>).
{{quote|'''Finding 2-1''': Modern martian environments may contain molecular fuels and oxidants that are known to support metabolism and cell division of chemolithoautotrophic microbes on Earth}}}}, ionizing radiation{{refn|name=ionizing_radiation|(see 3.6. Ionizing radiation at the surface page 891 of<ref name=MarsSpecialRegions2014/>).
{{quote|'''Finding 3-8''': From MSL RAD measurements, ionizing radiation from GCRs at Mars is so low as to be negligible. Intermittent SPEs can increase the atmospheric ionization down to ground level and increase the total dose, but these events are sporadic and last at most a few (2–5)days. These facts are not used to distinguish Special Regions on Mars.}}
{{quote|Over a 500-year time frame, the martian surface could be estimated to receive a cumulative ionizing radiation dose of less than 50 Gy, much lower than the LD90 (lethal dose where 90% of subjects would die) for even a radiation-sensitive bacterium such as E. coli (LD90 of ~200–400 Gy)}}
}}., UV radiation{{refn|name=UV|(see 3.5. Ultraviolet radiation on the surface of Mars page 901 of<ref name=MarsSpecialRegions2014/>).
{{quote|'''Finding 3-7''': The martian UV radiation environment is rapidly lethal to unshielded microbes but can be attenuated by global dust storms and shielded completelyby<1 mm of regolith or by other organisms.}} }}, and low atmospheric pressure{{refn|name=pressure|(see 3.4.3. Pressure of<ref name=MarsSpecialRegions2014/>).
{{quote|'''Finding 3-6''': Most terrestrial bacteria tested fail to grow below 2500 Pa. However, a small subset of bacteria havenow been identified that can reproduce (on rich hydratedagar media) in a ‘‘martian’’ atmosphere (anoxic, CO2)ataverage martian pressure (700 Pa) and 0°C. This fact isnot used to distinguish Special Regions on Mars.}}}} are not used to restrict special regions, because some Earth microbes tolerate them. The presence of multiple environmental factors simultaneously is also not used to restrict special regions because of the existence of polyextremophiles that can withstand multiple simultaneous extreme conditions{{refn|name=multifactor|(see 3.7. Polyextremophiles: combined effects of environmental stressors of<ref name=MarsSpecialRegions2014/>).
{{quote|'''Finding 3-9''': The effects on microbial physiology of more than one simultaneous environmental challenge are poorly understood. Communities of organisms may be able totolerate simultaneous multiple challenges more easily than individual challenges presented separately. What little is known about multiple resistance does not affect our current limits of microbial cell division or metabolism in response to extreme single parameters.}}}}.
In principle native Martian life could have additional capabilities, and so, be able to propagate at lower temperatures or with lower water activity (one suggestion is a mixture of water and [[hydrogen peroxide]] as internal solvent in the cells<ref name=peroxide_life>{{cite journal | title = A Possible Biogenic Origin for Hydrogen Peroxide on Mars | journal = International Journal of Astrobiology | volume = 6 | issue = 2 | pages = 147 | date = 2007-05-22 | first = Joop M. | last = Houtkooper |author2=Dirk Schulze-Makuch | doi = 10.1017/S1473550407003746 | arxiv = physics/0610093 |bibcode = 2007IJAsB...6..147H }}</ref> ). However, since these capabilities are unknown, they are not used to determine special regions.
The requirements also apply to spacecraft induced special regions. Missions need to study these in the planning phase, for instance the potential to create them through impact or sources of thermal energy foreign to Mars<ref name=MarsSpecialRegions2014/>. If a [[hard landing]] risks biological contamination of a special region, it has to be sterilized sufficiently to prevent this (COSPAR category IVc)<ref name=MarsSpecialRegions2014/>.{{refn|name=spacecraft_impact}}<ref name=MarsSpecialRegions2014/>.
Missions need to study their potential to create Spacecraft-Induced special regions during the planning phase and take action to make sure they are not inadvertently created. Spacecraft also need to avoid special regions if not sterilized sufficiently to prevent contaminating them{{refn|name=spacecraft_impact|Section 8. Summary of <ref name=MarsSpecialRegions2014/>
{{quote|Thus, during the planning phases, missions will study their own potential to create Spacecraft-Induced SpecialRegions by the presence of a lander itself or by non-nominaloperations during the descent phase and will take action toensure that Special Regions are not inadvertently created.Robotic spacecraft will need to avoid Special Regions if they are not clean enough to avoid contaminating those regions. Although current requirements are the same as those met by the Viking missions of the mid-1970s, no spacecraft sent to Mars since that time has been clean enough to enter a Special Region}}}}. The risk of spacecraft induced special regions needs to be evaluated separately for each mission, taking account of the spacecraft and the landing ellipse<ref name=MarsSpecialRegions2014/>.
There are currently no confirmed special regions. However there are many uncertain regions such as the recurring slope lineae. These are treated as special regions for the purposes of planetary protection, until more is known<ref name=appel/>.
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{{quote|''“So we have to do all of our search for life activities, we have to look for the Mars organisms, without the background, without the noise of having released Earth organisms into the Mars environment”''}}
See also
* [[Possible present day habitats for life on Mars (Incuding potential Mars special regions)]]
* [[Protecting Mars special regions with potential for life to propagate]] (extended version of this section)
===Revisions of the definition of a special region===
The definition of a special region has been revised several times. In the 2006 study it was implicit that a special region must be defined by warm enough temperatures combined with sufficient water activity. If the Mars surface is mapped using those requirements alone and requiring them to overlap, the map would be blank {{refn|(see page 941 of<ref name=MarsSpecialRegions2014/>)}}. The only place where habitats could occur for the 2006 report were deep below the surface, or perhaps places like the gully systems where water could be exposed to the surface dynamically from the subsurface.
However the 2014 study finds that though the temperature and water activity conditions are not present simultaneously, often they are present at the same location on the surface within a 24 hour period of each other due to the extreme day - night cycles on Mars. That then makes it possible that terrestrial biology could bridge the gap (e.g. retain the water through to warmer temperatures in the same day). For instance at the Curiosity and Viking sites temperatures in the daytime are regularly high enough for replication and at night relative humidity was above 0.6 and nearly always close to 1.0, and since both conditions occur in the same 24 hour period, there may be a way for organisms to connect the favorable aspects of these different periods through biotic adaptation {{refn|Referring to the Viking and Curiosity (MSL) landing sites they say (page 941 of<ref name=MarsSpecialRegions2014/>)
{{quote|... where in some seasons the temperature required for microbial replication was regularly reached during the driest part of the day, whereas at night, when the temperature was too low for replication, the relative humidity at the site was above 0.6 and nearly always close to 1.0. The non-overlap of the required values for a Special Region is reflected in Finding 4-12, but the fact that both could be reached within the same 24 h period, regularly, suggests that there may be a way for organisms to connect the favorable aspects of those periods across a bridge of biotic adaptation.}}}}
The report remarks that they didn't have any evidence yet that terrestrial organisms could bridge that gap, and they had some evidence that suggested it might be unbridgeable. However where the atmospheric pressure is above the triple point of water, precipitation that reaches the ground could melt and provide a temporary habitat. Also some materials such as clays, and the organisms themselves could retain more water than the soil itself. It also remarks on the potential occurrence of small-scale habitats, especially in the subsurface, not detectable with space instruments either existing or planned.
Before the 2014 report was published, both NASA and ESA took steps to have it reviewed independently. This 2015 review concurred with 29 findings of the original report. They did not support one of them and proposed modifications to 15 others<ref name=appel>[https://appel.nasa.gov/2016/03/09/mars-special-regions-redefined/ Mars Special Regions Redefined ] NASA Appel Knowledge Services News Digest</ref>. The 2015 review comittee in their report<ref name=MarsSpecialRegionsReview2015>Board, S.S., European Space Sciences Committee and National Academies of Sciences, Engineering, and Medicine, 2015. [https://www.nap.edu/catalog/21816/review-of-the-mepag-report-on-mars-special-regions Review of the MEPAG report on Mars special regions]. National Academies Press.</ref> said that they believe that some important aspects were not covered in the previous report{{refn|[https://www.nap.edu/read/21816/chapter/4 Chapter 2: The Assessment of the Potential of Terrestrial Lifeforms to Survive and Proliferate on Mars in the Next 500 Years], from <ref name=MarsSpecialRegionsReview2015/>}}. For instance:
* The possibility of terrestrial contamination blown in the Martian dust.
Although UV radiation would sterilize life quickly, this can be attenuated by the dust. Also the life can occur in larger cell chains, clumps or aggregates, and the cells in the interior of these aggregates can be protected from UV.
The review says that research so far is not sufficient to answer the question and that the possibility of this form of contamination could be confirmed or rejected in terrestrial Mars simulation chambers{{refn|In chapter 2 of <ref name=MarsSpecialRegionsReview2015/>:
{{quote|A potential problem with designating Special Regions on Mars is that viable microorganisms that survive the trip to Mars could be transported into a distant Special Region by atmospheric processes, landslides, avalanches (although this risk is considered minimal), meteorite impact ejecta, and lander impact ejecta. In addition to dilution effects, the flux of ultraviolet radiation within the martian atmosphere would be deleterious to most airborne microbes and spores. However, dust could attenuate this radiation and enhance microbial viability. In addition, for microbes growing not as single cells but as tetrades or larger cell chains, clusters, or aggregates, the inner cells are protected against ultraviolet radiation. Examples are methanogenic archaea like Methanosarcina, halophilic archaea like Halococcus, or cyanobacteria like Gloeocapsa. This is certainly something that could be studied and confirmed or rejected in terrestrial Mars simulation chambers where such transport processes for microbes (e.g., by dust storms) are investigated. The SR-SAG2 report does not adequately discuss the transport of material in the martian atmosphere.}}
}}
* The ability of multi-species microbial communities to alter dispersed small-scale habitats.
Cells in biofilms are embedded in a matrix of externally produced substances (such as polysaccharides, proteins, lipids and DNA) and adjust environmental parameters to make them more habitable{{refn|In chapter 2 of <ref name=MarsSpecialRegionsReview2015/>:
{{quote|where the cells are embedded in a self-produced extracellular matrix consisting of polysaccharides and proteins, which includes other macromolecules such as lipids and DNA. These so-called extrapolymeric substances (EPS) provide protection against different environmental stressors (e.g., desiccation, radiation, harmful chemical agents, and predators). Biofilms are highly organized structures that enable microbial communication via signaling molecules, disperse cells and EPS, distribute nutrients and release metabolites, and facilitate horizontal gene transfer.
The majority of known microbial communities on Earth are able to produce EPS, and the protection provided by this matrix enlarges their physical and chemical limits for metabolic processes and replication. EPS also enhances their tolerance to simultaneously occurring multiple stressors and enables the occupation of otherwise uninhabitable ecological niches in the microscale and macroscale. The presence of EPS within a microbial community has implications for several aspects of the SR-SAG2 report, including the physical and chemical limits for life, the dimension of habitable niches versus the actual resolution capability of today’s instruments in Mars orbit, colonization of brines, and tolerance to multiple stressors. In extreme cold and salty habitats (e.g., brines of sea ice and cryopegs in permafrost), EPS has been found to be an excellent cryoprotectant}}
}}. There are many examples of small-scale and even microscale communities on Earth including biofilms only a few cells thick. Microbes can propagate in these biofilms despite adverse and extreme surrounding conditions.
* microscale habitats that can't be detected from orbit.
The 2014 report briefly considers these. The 2015 review expands on this topic, and says that to identify such potential habitats requires a better understanding of the temperature and water activity of potential microenvironments on Mars, for instance in the interior of craters, or microenvironments underneath rocks. These may provide favourable conditions for establishing life on Mars even when the landscape-scale temperature and humidity conditions would not permit it.
{{refn|In chapter 2 of <ref name=MarsSpecialRegionsReview2015/>:
{{quote|There are many examples of small-scale and microscale environments on Earth that can host microbial communities, including biofilms, which may only be a few cell layers thick. The biofilm mode of growth, as noted previously, can provide affordable conditions for microbial propagation despite adverse and extreme conditions in the surroundings. On Earth, the heterogeneity of microbial colonization in extreme environments has become more obvious in recent years. To identify Special Regions across the full range of spatial scales relevant to microorganisms, a better understanding of the temperature and water activity of potential microenvironments on Mars is necessary. For instance, the interior of the crater Lyot in the northern mid-latitude has been described as an optimal microenvironment with pressure and temperature conditions that could lead to the formation of liquid water solutions during periods of high obliquity (Dickson and Head 2009). Craters, and even microenvironments underneath and on the underside of rocks, could potentially provide favorable conditions for the establishment of life on Mars, potentially leading to the recognition of Special Regions where landscape-scale temperature and humidity conditions would not enable it.}}
}}
* Ice close to the surface needs to be taken account of for spacecraft induced special regions.
The 2014 report looked at distributions of ice and concluded that ice in the tropics is buried too deep to be a consideration{{refn|<ref name=MarsSpecialRegions2014/>
{{quote|SR-SAG2 Finding 5-3: Depths to buried ice deposits in the tropics and mid-latitudes are considered to be >5 m.}}}}
However the 2014/5 review corrected this due to evidence of ice present at depths of less than one meter in pole-facing slopes{{refn|
Chapter: 3 Martian Geological and Mineralogical Features Potentially Related to Special Regions, [https://www.nap.edu/read/21816/chapter/5#24 SNOW, ICE DEPOSITS, AND SUBSURFACE ICE] of <ref name=MarsSpecialRegionsReview2015/>
{{quote|Revised Finding 5-3: In general, depths to buried ice deposits in the tropics are considered to be >5 m. However, there is evidence that water ice is present at depths of <1 m on pole-facing slopes in the tropics and mid latitudes. Thus, a local detailed analysis for a particular area is necessary to determine if it could be a Special Region.}}
}}
* Utility of maps
The 2014 report<ref name=MarsSpecialRegions2014/> provided a map of regions of Mars where there may be ice below the surface as well as potential RSL's. The 2015 review however said that such maps are most useful if accompanied by cautionary remarks on their limitations, as they are subject to change with new discoveries and because of the potential for microhabitats<ref name=MarsSpecialRegionsReview2015/>.
===Caution on use of maps===
The committees for the 2014/5 revisions caution that maps of regions with higher or lower probability to host special regions should be accompanied by cautionary remarks on their limitations. Any such map can only represent the current state of konwledge, which is incomlete and subject to change as new information is obtained.
{{refn|[https://www.nap.edu/read/21816/chapter/7 chapter 5] of <ref name=MarsSpecialRegionsReview2015/>
{{quote|In general, the review committee contends that the use of maps to delineate regions with a lower or higher probability to host Special Regions is most useful if the maps are accompanied by cautionary remarks on their limitations. Maps that illustrate the distribution of specific relevant landforms or other surface features can only represent the current (and incomplete) state of knowledge for a specific time—knowledge that will certainly be subject to change or be updated as new information is obtained.}}
}}
Instead each mission needs to be considered on a case by case basis using all the available data. They give the example of Schiaparelli where, for example, all HiRISE images of the landing site were inspected for the possible presence of RSL's.
{{refn|[https://www.nap.edu/read/21816/chapter/7 chapter 5] of <ref name=MarsSpecialRegionsReview2015/>
{{quote|In the case of Schiaparelli, for example, all available data for the proposed site in Meridiani Planum were analyzed to determine if Special Regions existed within the landing ellipse. In particular, all HiRISE images were inspected for the possible presence of RSL.}}
}}
For more details about the characterization of Mars special regions for purposes of planetary protection see:
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Some targets are easily categorized. Others are assigned provisional categories by COSPAR, pending future discoveries and research.
The 2009 COSPAR Workshop on Planetary Protection for Outer Planet Satellites and Small Solar System Bodies covered this in some detail. Most of these assessments are from that report, with some later refinements. This workshop also gave more precise definitions for some of the categories:<ref name=smallsolarsystembodies>[
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<br><br>
Recommendation: Approaches to achieving planetary protection for missions to icy Solar System bodies should employ a series of binary decisions that consider one factor at a time to determine the appropriate level of planetary protection procedures to use.}}
==Laws for a restricted category V sample return==
Although the forwards direction is only covered by the Outer Space Treaty there are many other laws that protect us in the backwards direction of a sample returned from Mars (say) to Earth. Margaret Race looked in detail at the legal processes that would have to be completed before we can return a sample from Mars to Earth, even to a purpose built receiving facility.
Before a sample return, we have to accomplish, in this order
* Several years: Formal environment impact statement for NEPA + laws on quarantine to be enacted, involving broad public consultation. The average length of time for an EIS in the twelve months ending 30th September 2016 was 46 months (see the DOE's Lessons Learned Quarterly Report).
* Several years: Presidential review of potential large scale effects on the environment. This has to be done after all the other domestic legislation is completed.
* Can be done alongside the other work: International treaties to be negotiated and domestic laws of other countries
This covers only a few of the main points
In more detail, summary of Margaret Race's findings<ref name=race>Race, M.S., 1996. [https://www.ncbi.nlm.nih.gov/pubmed/11538983 Planetary protection, legal ambiguity and the decision making process for Mars sample return.] Advances in Space Research, 18(1-2), pp.345-350.</ref>:
She found that under the National Environmental Policy Act (NEPA) (which did not exist in the Apollo era) a formal environment impact statement is likely to be required, and public hearings during which all the issues would be aired openly. This process is likely to take up to several years to complete.
During this process, she found, the full range of worst accident scenarios, impact, and project alternatives would be played out in the public arena. Other agencies such as the Environment Protection Agency, Occupational Health and Safety Administration, etc, may also get involved in the decision making process.
The laws on quarantine will also need to be clarified as the regulations for the Apollo program were rescinded. In the Apollo era, NASA delayed announcement of its quarantine regulations until the day Apollo was launched, so bypassing the requirement for public debate - something that would be unlikely to be tolerated today.
It is also probable that the presidential directive NSC-25 will apply which requires a review of large scale alleged effects on the environment and is carried out subsequent to the other domestic reviews and through a long process, leads eventually to presidential approval of the launch.
Then apart from those domestic legal hurdles, there are numerous international regulations and treaties to be negotiated in the case of a Mars Sample Return, especially those relating to environmental protection and health. She concluded that the public of necessity has a significant role to play in the development of the policies governing Mars Sample Return}}
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==Containment and quarantine for restricted Category V sample return==
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