Assessment of Planetary Protection Requirements for Mars Sample Return Missions (2009) / Chapter Skim
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6 Sample Containment and Biohazard Evaluation
6 Sample Containment and Biohazard Evaluation
Pages 50-57
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From page 50... ...
If anything, however, the discoveries over the past decade about Mars and about terrestrial extremophiles have supported an enhanced potential for liquid water habitats and, perhaps, microbial life on Mars, thus making it appropriate to continue this conservative approach. A factor potentially complicating the policies and protocols relating to sample containment and biohazard evaluation is the de facto internationalization of a Mars sample return mission.
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From page 51... ...
BIOHAZARDS TESTING Following publication of the 1997 NRC report Mars Sample Return: Issues and Recommendations,6 two additional reports, the NRC's The Quarantine and Certification of Martian Samples7 and NASA's A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth, 8 were published in 2002. The latter report provided a set of protocol release criteria indicating when and under what conditions martian samples could be released from containment in an SRF.
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From page 52... ...
The present committee further supports the NRC's 1997 recommendation that, once samples have been delivered to an SRF, NASA maintain a conservative approach in implementing the protocol and in making decisions about the intentional release of pristine martian samples from containment. Presumably, in the time leading up to sample return, there will be continuing refinements in methods for sample handling and in the development of new analytical instrumentation for characterizing and testing samples.
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From page 53... ...
for biohazard testing must carefully consider heterogeneities in the spatial distribution of such features and the impact on the distribution of microorganisms and their by-products within samples. Especially important as a source of spatial heterogeneity in the microscale distribution of habitable environments that could support living organisms are fluid inclusionssmall quantities (~microliters)
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From page 54... ...
gypsum crystal with included bands of hematite mud, with c1 showing Fe-oxide/Fe-silicate-coated pollen and wood extracted from gypsum and c2 showing microbes within a fluid inclusion in gypsum; (d) interior of hematite concretion, including reworked gypsum (large white grain near top)
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From page 55... ...
Optimal designs are likely to require end-to-end testing of a variety of Mars analog materials to refine instrument designs, define necessary instrument sensitivities, and determine minimum sample volumes needed for obtaining reliable results with different types of materials. CONCLUSIONS AND RECOMMENDATIONS Planetary protection considerations require that martian materials be securely contained within a sample canister for their journey from Mars, through collection and retrieval on Earth, and subsequent transport to, and confinement in, a sample-receiving facility.
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From page 56... ...
The distribution of extant and fossil organisms and biomolecules in rocks, soils, and ices is heterogeneous at microscopic scales of observation, and this heterogeneity requires careful consideration because it complicates the selection of representative aliquots for biohazards testing. Recommendation: Future protocol guidelines should carefully consider the problems of sample heterogeneity in developing strategies for life detection analyses and biohazards testing in order to avoid sampling errors and false negatives.
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From page 57... ...
SAMPLE CONTAINMENT AND BIOHAZARD EVALUATION 57 10 L Lemelle, M
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