A new report that could make it simpler to send spacecraft to some areas of
Mars while still protecting the planet from Earth-based contamination was
presented today at a press conference at the 53rd annual meeting of the
American Astronomical Society's Division for Planetary Sciences by Planetary
Science Institute Senior Scientist Amanda Hendrix.
The report from the National Academies of Sciences, Engineering, and
Medicine identifies criteria that could allow robotic missions to certain
locations on Mars to be carried out with less restrictive "bioburden"
requirements, which are designed to prevent harmful contamination by
Earth-based microbes at Mars.
"The Committee on Planetary Protection, a standing committee of the National
Academies Space Studies Board, was tasked by NASA to write a report
discussing criteria that could be used to designate regions on Mars where
missions can land with less stringent bioburden requirements than currently
in place. Currently, meeting planetary protection requirements—for instance,
using rigorous sterilization techniques—can be seen as imposing, costly and
complex, and it could be that these restrictions can be simplified and
modernized, in some cases, which can help make some areas of Mars more
accessible," said Hendrix, co-chair of the committee that wrote the report.
"The report suggests techniques for modernizing and providing flexibility in
planetary protection implementation. One way to do this is by utilizing a
risk management approach, that could be tailored to individual missions'
needs," Hendrix said. "The Committee's findings can lead to making portions
of Mars more accessible to both commercial and government endeavors by
relaxing planetary protection requirements while remaining careful about
access to potential habitable zones."
In this report, the Committee focused on regions on Mars that might not be
negatively impacted if visited by spacecraft that are not stringently
sterilized. For missions that do not access the subsurface, such regions
could include a significant portion of the surface of Mars, because the UV
environment is so biocidal that terrestrial organisms are, in most cases,
not likely to survive more than one to two sols, or Martian days. For
missions that access the subsurface (down to 1 meter), regions on Mars
expected to have patchy or no water ice below the surface might also be
visited by spacecraft more relaxed bioburden requirements, because such
patchy ice is likely not conducive to the proliferation of terrestrial
microorganisms.
The report finds that it is imperative that any mission sent to Mars with
reduced bioburden requirements remain some conservative distance from any
subsurface access points, such as cave openings. Furthermore, though less
stringent than current requirements, these missions with relaxed bioburden
requirements would still need some level of cleanliness, which could be
achieved for instance using standard aerospace cleanliness practices.
"The whole purpose of planetary protection protocols is to minimize the risk
of harmful contamination; this means minimizing the risk of introduction of
terrestrial biological material that could confound future life detection
experiments. This is really important in the case of Mars," Hendrix said.
"At Mars we know that the surface is almost certainly uninhabitable for
terrestrial microorganisms, due to the harsh UV environment; however,
subsurface regions such as caves, shielded from radiation, could be
habitable zones, for terrestrial and/or indigenous Martian life.
"The report will help in the search for life on Mars by identifying those
areas on its surface for which planetary protection standards for spacecraft
must be most restrictive," Hendrix said. "Also, by potentially easing
planetary protection burdens in the exploration of other areas, NASA could
enable more missions to Mars that help us understand the planet and its
environment, even if these missions are not pursuing astrobiological
studies."
The committee's findings apply specifically to missions for which NASA has
responsibility for planetary protection. For commercial missions in which
NASA has no role or connection, the U.S. government still needs to designate
a regulatory agency to authorize and continually supervise space activities
in accordance with the Outer Space Treaty, the report says. The study was
funded by NASA.
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