Preventing the Forward Contamination of Mars (2006) / Chapter Skim
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7 Assessing Non-Living Contaminants of Concern
7 Assessing Non-Living Contaminants of Concern
Pages 105-110
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From page 105... ...
Planetary protection of Mars has previously emphasized the need to restrict a spacecraft's burden of living organisms to prevent biological contamination of Mars and to avoid jeopardizing experiments designed to detect life there. But because many of the newer techniques for detection of life depend on the measurement of trace quantities of specific molecules, it is important that planetary protection measures also address the level of nonliving contamination of spacecraft that could confound with false positives the results obtained with such techniques.
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From page 106... ...
. Preventing the development of "microbial islands" or growth pockets aboard spacecraft and/or landers will depend in part on the ability to limit the contact between microbial cells, organic substrates, oxidants such as Fe(III)
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From page 107... ...
Salts, dust, aerosols, and fingerprints are all of concern for the control of contamination, both on the surfaces and within the interior spaces of spacecraft, as well as for the potential transfer of contaminants from spacecraft components to Mars. Nitrogen as a contaminant could take many forms in addition to particulate matter: it could also be present in nitrogenous salts and in volatile phases, including as N2 gas; the reduced species ammonia, hydrazine, and cyanide; and the oxidized forms N2O and nitrogen oxides (NOx)
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From page 108... ...
108 PREVENTING THE FORWARD CONTAMINATION OF MARS Any Mars mission that enters the martian atmosphere and reaches the surface will emit solid, liquid, or gaseous nonbiological materials that are foreign to the Mars environment, including propulsion exhaust products in amounts ranging from as little as a few kilograms (as was the case for Pathfinder) to as much as 30 metric tons for a Mars excursion vehicle with a crew of four people and a surface payload of 25 metric tons (MSFC, 1991)
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From page 109... ...
Volatile compounds can be monitored during a thermal bakeout procedure in which spacecraft components are heated to release volatile compounds and thus reduce the rate of escape and migration of such volatiles during the mission (Mahaffy et al., 2003)
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From page 110... ...
110 PREVENTING THE FORWARD CONTAMINATION OF MARS Husted, R.R., I.D. Smith, and P.V.
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