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In January of 2004 NASA was directed by the President of the United States to setting a goal to establish a permanent human tended scientific outpost on the Moon by 2015-2020. Discussions on what kind of facilities on the Moon would be most beneficial to science have already begun.
One of the highest priority goals for the NASA Mars exploration program has been how to proceed with the return of Martian soil and rock samples directly to Earth for extensive laboratory analysis. However scientific debates exist on how to obtain pristine samples from Mars without introducing terrestrial contaminants and also for preventing the back contamination of the Earth’s biosphere by putative Martian microbes. In 1976, the Viking Labeled Release experiment provided peer-reviewed scientific evidence for possible microbial activity in the upper soil layers of Mars in two different locations on the planet. Although the LR evidence is not considered as absolute proof of life on Mars by many in the scientific community, the Viking LR data should be taken seriously as an important signpost that life, either as dormant endospores (which may have been revived on the addition of the LR nutrient solution), or found as a currently thriving microbial community, might pose a serious risk to the terrestrial biosphere in the event of a sample return spacecraft failure. Examples of spacecraft technological failures include most recently the British built Beagle 2 lander, the NASA Mars Climate Orbiter and Mars Polar Lander. These examples show there is no guarantee of a 100% foolproof spacecraft.
In 2001 the Space Studies Board of the National Research Council published that the likelihood of life on Mars is low, "but it is not zero" and proposed the construction of a level-4 biohazard containment facility "like no other on the Earth". Since at this time we cannot guess whether any putative Martian organisms would be toxic or pathogenic to Earth life, every effort should be made to ensure that the terrestrial biosphere is not contaminated.
Recent Mars Sample Return (MSR) scenarios have focused on a direct return to the surface of the Earth by means of a passive reentry capsule similar to the Stardust sample capsule but designed to use atmospheric friction and ablating to slow its decent instead of a parachute. This scenario offers less planetary protection than LEO examination by a specially trained scientific crew aboard the ISS or space shuttle.
While a number of Mars Sample Return strategies have been published since the 1976 Viking mission, probably the most comprehensive concerning examination in LEO is the 1981 The Antaeus Report: Orbiting Quarantine Facility (NASA SP-454).
Although the Antaeus Report demonstrated the feasibility of examining planetary samples in LEO it did not offer Earth's biosphere maximum protection against back contamination hazards due to possible catastrophic failure and reentry of the orbiting quarantine facility or space shuttle.
A human tended Planetary Quarantine Laboratory as part of a scientific outpost on the Moon would offer 100% protection of Earth's biosphere against any toxic or pathogenic bioactive materials from Mars or any other solar system samples returned.
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