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Assessment of Planetary Protection Requirements for MARS: Sample Return Missions
biological-hazard perspective, risk is generally a function of hazard (the agent) and the probability that a negative event will occur based on the tasks to be performed with the agent. Consequently, risk-mitigation strategies will focus on eliminating the hazard and/or reducing the probability of a negative event. Both will lead to a risk that is considered acceptable, since achieving zero risk is not possible.
NASA has not yet performed the specific type of risk assessment that might be associated with the design of, for example, a biosafety level (BSL)-4 facility. Such an assessment is premature given that planning for both a Mars sample return mission and an SRF is currently only at the stage of conceptual definition. However, NASA has done a good job so far of considering risk. Issues of biosafety, biosecurity, and biocontainment were discussed at length throughout the process by which the draft protocol was assembled and in reviews and analyses of current methods, instruments, equipment, and facilities used for biocontainment versus planetary science containment. Considerable attention has been paid to the nature of the agent (i.e., pristine martian materials) and to the possible risks associated with it. Finally, U.S. and international experts on biosafety, biocontainment, and risk assessment have participated in many of the past discussions of a Mars sample return mission and an SRF.
TIMESCALE FOR ESTABLISHING A SAMPLE-RECEIVING FACILITY
Although there still is no facility in existence anywhere that combines the requisite biocontainment levels, cleanliness conditions, instrumentation, and other features needed for the characterization and testing of returned martian samples, there is an increasingly clear understanding of what will be required and how it can be accomplished. In addition, existing recommendations provide different viewpoints concerning how and when such an SRF should be established (Table 7.1).
It has been estimated that the planning, design, site selection, environmental reviews, approvals, construction, commissioning, and pre-testing of a proposed SRF will occur 7 to 10 years before actual operations begin.17,18,19 In addition, 5 to 6 years will likely be required for refinement and maturation of SRF-associated technologies for safely containing and handling samples to avoid contamination and to further develop and refine biohazard-test protocols. Many of the capabilities and technologies will either be entirely new or will be required to meet the unusual challenges of integration into an overall (end-to-end) Mars sample return program.
It will be particularly important to recognize the added lead time needed to establish an SRF while avoiding complications that could jeopardize mission success. Significant planning time for hardware development and testing must be allocated to allow for selection of the best technology concepts among various alternatives proposed and tested. As noted in the iMARS preliminary report,20 planetary protection and sample receiving are important considerations for designing the Mars sample return mission architecture. These concerns can significantly affect design and time ramifications, with direct and indirect implications for both flight and ground-related mission elements, including control of forward contamination (e.g., to avoid contaminating samples with hitchhiking terrestrial organisms during the collection and packaging of samples on Mars), breaking the chain of contact with Mars, designing a reliable sample container, ground recovery, development of an SRF, sample handling and controls for avoiding contamination, and biohazard-testing protocols. For example, even as a quarantine facility is being planned, there is a need to construct and test mock-ups of clean-room/containment combinations.
The experiences from the Genesis and Stardust sample return missions have demonstrated the increased importance of scrutinizing the entire sample-handling and containment chain, including the landing site characteristics, ground recovery, and transport to ground facilities, not just the quarantine or containment laboratory per se (Stardust and Genesis did not have quarantine laboratories). In addition to technology and hardware developments, it is also important to acknowledge the uncertain lead time that will be needed to accommodate the diverse regulatory review and approval processes that will apply to biocontainment laboratory construction in the post-9/11 era. There is likely to be active public involvement in the decision-making process for a proposed SRF and perhaps even legal challenges that would introduce complications not typically experienced in mission planning.21 To avoid jeopardizing mission success, there is a strong need to incorporate all aspects of an SRF and sample handling at the earliest stages of Mars sample return mission planning.