Preventing the Forward Contamination of Mars (2006) / Chapter Skim
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8 A Path Forward for Planetary Protection in the 21st Century
8 A Path Forward for Planetary Protection in the 21st Century
Pages 111-123
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From page 111... ...
many of the existing policies and practices for preventing the forward contamination of Mars are outdated in light of new scientific evidence about Mars and current research on the ability of microorganisms to survive in severe conditions on Earth; (2) a host of research and development efforts are needed to update planetary protection requirements so as to reduce the uncertainties in preventing the forward contamination of Mars; (3)
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From page 112... ...
If applied properly, they should allow researchers, engineers, and planetary protection officials to improve both microbial detection and bioburden reduction methods compared to those currently being used (see Chapter 6)
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Thus, the committee's recommendations 12 through 14 advise more stringent requirements for bioburden reduction for Mars missions. Much of the uncertainty about the risks of contaminating the martian bio sphere involves the survival and growth rates of microbial contaminants that may be present on spacecraft when they arrive.
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From page 114... ...
Recommendation 3. Future missions to Mars should plan for the effective implementation of planetary protection requirements at the earliest stages of mission and instrument design, and engineers should be provided with a selection of effective, certified tools for bioburden reduction.
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From page 115... ...
Recommendation 4 of this report addresses the need to update planetary protection requirements, if necessary, in 3As noted in Chapter 6, NASA is currently investigating advanced microbial detection and bioburden reduction methods, but additional research on these technologies is needed. 4Analytical models such as rarefaction or Bayesian inference should be used to ensure the completeness of a survey, and a sufficient number of nucleotides per gene sequence should be used to differentiate among unique sequences (e.g., Altekruse et al., 2003)
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From page 116... ...
Recommendation 8. NASA should sponsor studies of bioburden reduction techniques that are alterna tives to dry-heat sterilization.
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Recommendation 11. NASA should take the following steps to transition toward a new approach to assessing the bioburden on spacecraft: · Transition from the use of spore counts to the use of molecular assay methods that provide rapid estimates of total bioburden (e.g., via limulus amebocyte lysate (LAL)
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From page 118... ...
However, because a number of Mars missions are planned for launch prior to 2016, the committee recognizes the need for an interim plan that updates existing planetary protection requirements to reflect new scientific knowledge about Mars and terrestrial microorganisms. The recommendations presented below, based on existing planetary protection protocols, concern planetary protection requirements that should be implemented during the interim period from now until the transition to new practices is completed.
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From page 119... ...
In particular, some types of biodetection experiments may require extraordinary levels of cleanliness, whereas others may have much less stringent requirements. Thus the committee believes that the IVa and IVb mission categories are no longer a useful way to determine planetary protection requirements for Mars landers.
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However, many, but not all, spacecraft components would in such a case experience great bioburden reduction through extreme surface heating. The most likely type of crash impact, terminal impact, would expose only some of the nominally nonexposed surfaces.
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From page 121... ...
4 Viking post-sterilization bioburden reduction for the whole spacecraft.a Category IVs missions accessing Currently, this would likely mean baking the spacecraft in a manner similar locations determined to have to that employed in the Viking mission, although the committee encourages long-lived liquid water NASA to investigate other technologies to this same end. 5 The committee cannot currently specify the technology that could become Category IVs missions accessing available to attain zero microorganisms on Mars-bound spacecraft.
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Recommendation 15. NASA should sponsor research on how to implement level 3, 4, and 5 bioburden reduction requirements in practical ways.
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2004a. Species differentiation of a diverse suite of Bacillus spores using mass spectrometry based protein profiling.
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