Planetary protection rules for Mars could be relaxed | Daily Planet


A new report of the Planet Protection Committee of the National Academies, co-chaired by Amanda Hendrix of the Planetary Science Institute and science policy consultant Joseph Alexander, recommends that the rules regarding planetary protection – strict procedures to ensure that terrestrial microbes do not contaminate other worlds and vice versa – can be relaxed for certain missions to Mars.

The committee examined the natural sterilizing effects of the Martian environment and came to the conclusion that the constraints on bioburden, or the amount of microbial hitchhikers allowed on spacecraft bound for Mars, could be lowered to missions working at or near the surface. Only basic sterilization would be necessary for rovers digging or drilling less than a meter underground, unless they are near a cave entrance, or if remote sensing data shows ice from water could be present in the shallow subsurface. The panel also said that planetary protection for Mars missions could be addressed using a risk management approach rather than rigid sterilization requirements, which often increase the cost of a project.

An important thing to remember about NASA’s planetary protection guidelines is that they only apply to the agency’s own missions. For trade missions, the U.S. government has yet to designate a regulatory agency that could ensure compliance with the Outer Space Treaty, which governs the activities of all nations in space.. Right now, trade space missions can avoid planetary protection if they choose, which the report recognizes as a major flaw.

The conclusions of the Academy panel are consistent with what I asked, along with my colleague Alberto Fairén of the Center for Astrobiology of Madrid, in a 2013 commentary titled “The overprotection of Mars.” We felt that unnecessary and costly sterilization measures hamper future exploration of Mars, and that strict requirements should only be applied in cases where we could reasonably expect to encounter Martian life.

But on other points, I do not agree with the conclusions of the committee. The first is that native life on Mars, if it exists, cannot be distinguished from contamination on Earth. In a 2017 article, a large scientific team, including Fairén and myself, argues that we should in fact be able to make such a distinction. Either Martian life would be biochemically distinct from terrestrial life, in which case the differences should be apparent, or it is very similar, in which case it could probably be pinned to the lower branches of the tree of life, having diverged from an ancestor. common for a long time. since. The committee is right, however. Terrestrial contamination would make it more difficult to identify and characterize putative Martian life, and should therefore be avoided.

The other conclusion I disagree with is that there could be no life in the ice-free top meter of the Martian surface. The possibilities of life existing in shallow subsoils, especially in salt rocks, were discussed extensively during the 2019 Conference on Existing Life on Mars in Carlsbad, New Mexico. There are a lot of salty rocks on Mars, especially in the southern highlands, where salt-loving photosynthetic microbes could make their living near the surface. Microbes in salt can obtain vital water directly from the atmosphere, as many salts, including common sodium chloride, are able to draw moisture from the air. So, Martian life may not need the water from the ground at all.

On matters like this, I think we tend to show some earthly arrogance in our assumptions about life on Mars. If native Martian life existed, it would likely be much better suited to its home planet than Earth’s late arrivals would. It would have taken billions of years to understand the evolutionary adaptations of the Red Planet, unlike terrestrial organisms accustomed to much warmer and wetter conditions, and generally not accustomed to dealing with a combination of drought, ultraviolet light and sunlight. aggressive chemicals. Because of this, the threat that we contaminate Martian life may be less than we fear.

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