Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies Framework for Decision Making (1998) / Chapter Skim
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8 Conclusions and Recommendations
8 Conclusions and Recommendations
Pages 75-82
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From page 75... ...
Because of this direct evidence, and because there is no indirect evidence for recent or past liquid water on the Moon (although small amounts of polar ice have recently been discovered) , the potential for a living entity to be present in returned samples is negligible.
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From page 76... ...
It is unlikely that ice-filled voids, which might have attenuated that radiation, are present today within the upper reaches of Phobos and Deimos that are accessible to sample return missions, because typical subsurface temperatures are far too high for ice to exist in equilibrium. On the other hand, biological materials, if any, could conceivably have been protected in ice pockets at depth for considerable periods of time, transported more recently to near-surface environments by catastrophic collisional disruption, and subsequently reassembled in Mars orbit and by near-surface processes of regolith turnover.
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From page 77... ...
Furthermore, pockets of volatile compounds within chondritic materials could potentially shield dormant organisms from radiation damage. For these reasons, although the potential for a living entity to be present in returned samples from C-type asteroids is extremely low, the task group could not conclude that it is necessarily zero.
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From page 78... ...
, represents a valuable source of material for the evaluation of the composition and characteristics of objects throughout the solar system. Because interplanetary dust particles are derived from a variety of sources, including interstellar grains and debris from comets, asteroids, and possibly planetary satellites, IDPs cannot be viewed as a distinct target body.
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From page 79... ...
Table 8.1 summarizes the results of the task group's assessment. It is important to note that the task group' s recommended approach is provided only as a guide and not as an inflexible protocol for determin TABLE 8.1 Summary of Currently Recommended Approach to Handling Samples Returned from Planetary Satellites and Small Solar System Bodies Assessed by the Task Group on Sample Return from Small Solar System Bodies No Special Containment and Handling Warranted Beyond What Is Needed for Scientific Purposes Ia High Degree of Confidence II Strict Containment and Handling Warranted Ib Lesser Degree of Confidencea The Moon Phobos Europa lo Deimos Ganymede Dynamically new cometsb Callisto P-type asteroids Interplanetary dust particlesC C-type asteroids D-type asteroids Undifferentiated metamorphosed asteroids Interplanetary dust particlesd Differentiated asteroids All other comets Interplanetary dust particlese 7 aSubcolumn Ib lists those bodies for which confidence in the recommended approach is still high but for which there is insufficient information at present to express it absolutely.
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From page 80... ...
Strict containment and handling requirements are also warranted for interplanetary dust particles collected near these bodies unless they are sampled in a way that would result in exposure to extreme temperatures, e.g., spike heated. For samples that are returned from planetary satellites and small solar system bodies and that warrant containment, the concerns about biohazards or large-scale adverse effects on Earth are similar to those identified earlier for Mars (NRC, 1997~.
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From page 81... ...
Recommendation: The planetary protection measures adopted for the first sample return mission to a small body whose samples warrant special handling and containment should not be relaxed for subsequent missions without a thorough scientific review and concurrence by an appropriate independent body. SCIENTIFIC INVESTIGATIONS TO REDUCE UNCERTAINTY Identified by the task group in Chapters 2 through 6 is scientific research that could help to reduce the uncertainty in its assessment of the potential for a living entity to be contained in or on samples returned from planetary satellites and small solar system bodies.
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