Safe on Mars Precursor Measurements Necessary to Support Human Operations on the Martian Surface (2002) / Chapter Skim
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5. Potential Hazards of the Biological Environment
5. Potential Hazards of the Biological Environment
Pages 37-44
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From page 37... ...
Subcellular disease agents, such as viruses and priors, are biologically part of their host organisms, and an extraterrestrial source of such agents is extremely unlikely." The uncertainty surrounding whether or not life exists on Mars may not be resolved until after astronauts arrive on the planet (NRC, 1997~.2 of course, if life does exist on Mars, it could represent a biological hazard to astronauts. 2Some argue that since no life-form, or no conclusive evidence of hazardous life, was identified in meteorites from Mars found on Earth, there is no biohazard threat from Mars.
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From page 38... ...
In light of experience gained during Apollo missions to the Moon, a previous NRC the uncertainty makes it impossible to prove that meteorites from another planet have never had an effect on Earth's biosphere (NRC, 1997~. These considerations, and the consideration that a goal of future human missions will be to search for life-forms in Martian oases, if those oases exist, negate the argument that there is no biohazard threat from Mars based on the existence of sterile Martian meteorites.
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From page 39... ...
. The committee recommends that NASA conduct a precursor in situ experiment to determine if organic carbon is present at a location as close as reasonably possible to the landing sites selected for human missions to Mars.
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From page 40... ...
If no measurement technique can be used to determine if organic carbon is present above the life-detection threshold, or if organic carbon is detected above that threshold, a contained sample should be returned to Earth for characterization prior to sending humans to Mars. if No Organic Carbon is Delected If a precursor in situ organic carbon experiment can determine that no organic carbon is present above the life-detection threshold, the committee recommends that NASA judge the near surface on Mars at the landing site to be a ZMBR.
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From page 41... ...
Sample Return: Additional Benefits The Viking lander experiments were criticized because life-detection tests gave presumably false positive experimental results in some cases and clearly unexpected results in other cases, apparently due to the complex chemistry of the Martian soil. A secondary, though not mandatory, benefit of a precursor sample return mission is that a returned sample would allow researchers to establish effective and reliable testing methods that would reduce the risk of false positive or false negative results.
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From page 42... ...
42 SAFE ON MARS Precursor Organic Carbon Test: Critical Detection Limit to Be Determined by NASA · Zone of minimal biological risk established for like materials in like geologic settings · No precursor sample return required · Zone of minimal biological risk established · No life-forms present Negative result Positive or inconclusive result · Minimal biological risk zone not established · Possible life-form present · Precursor sample return from specific location required L _ Test for Martian life-form ~ Negative result Positive result _ Test for life-form infectivity to humans _ Not hazardous to humans _~ Hazardous to humans · Astronauts may not · Astronauts may operate safely in operate safely in presence presence of life- of life-form form · Life-form still represents an eco hazard to Earth FIGURE 5.1 Mars biology testing protocol. _~ ~l Test for life-form impact on Earthis biosphere _ No impact Possible impact 1 1 1 1 _ · Astronauts may operate safely in presence of life-form Ecohazard present
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From page 43... ...
Other protocols may need to be established if, for unforeseen reasons, it is not possible to isolate the return vehicle. In that case, life-detection tests must be conducted within the near-surface Martian regolith that 43 could adhere to the outside of the return vehicle when it lifts off from the Martian surface, unless precursor mission measurements (in situ or sample return)
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From page 44... ...
The committee was faced with the question of whether or not NASA must fully characterize the mineralogy of the dust and soil that is, the chemical composition and the physical form prior to the first human mission to Mars. The answer to this question is complicated by the fact that very little is known about Martian airborne crust and soil.
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