necessary to include the needed equipment and personnel in a design for the facility. Most particularly, these studies will include experiments that seek to demonstrate the presence of microbial life by methods that are conducive to microbial replication with resulting expansion of the numbers of viable organisms, or their genomes (Chapter 2). Examples of these experiments are as follows:

  1. Attempts to isolate infectious microbes by providing environmental conditions and substrates for growth, either conditions that resemble those on Mars or terrestrial conditions that the new microbe might find hospitable;

  2. Attempts to infect animals, plants, cell cultures derived from terrestrial life forms, or bacteria in which a martian genome could replicate; and

  3. Attempts to detect genomes (either RNA or DNA) by polymerase chain reaction (PCR) or similar techniques in which all or part of the genome is amplified by several orders of magnitude.

Because of constraints both on the amount of sample to be returned and on the range of equipment that can be available in the quarantine facility, the experimental protocol should focus on molecular biological techniques (e.g., PCR) and minimize to the extent feasible experiments involving whole organisms.

Use of PCR within the quarantine facility will require special precautions. Because the technique is extremely sensitive it is vulnerable to false positives caused by contamination. PCR experimentation should be carried out by specially certified technicians in a dedicated space within the quarantine facility which is effectively isolated from activities elsewhere in the facility.

In the event that Mars samples contain organic carbon yet are found to be incapable of infecting the limited range of species or ecosystems that can be tested in the BSL-4 quarantine facility, unqualified release of the samples is not justified. Such samples should remain in the “uncertain” category of life detection. However, it may be desirable to downgrade the required level of biocontainment for those samples from BSL-4 to BSL-3 (see Chapter 6), because the less-stringent standards of BSL-3 permit a larger facility in which more complex testing can be conducted (e.g., examination of the impact of martian material on a model of the marine microbial ecosystem). A sufficiently broad range of testing at this level could conceivably justify the release of unsterilized material containing martian organic compounds from quarantine, if any remains after the program of testing.

Release of Samples from the Quarantine Facility

The primary charge to COMPLEX in defining the present study was to consider the question, What are the criteria that must be satisfied before martian samples can be released from the facility? Summarizing the content of this chapter, COMPLEX recommends the following:

Recommendation

  • If the samples returned from Mars contain evidence of life, or if evidence of life is equivocal (e.g., organic matter is present), aliquots that have been treated by the application of heat and/or gamma radiation to levels more than adequate to kill any known terrestrial organism (Chapter 5) should be certified for release from the Mars Quarantine Facility.

  • If the samples contain evidence of life, or if evidence of life is equivocal, removal of untreated aliquots from the Mars Quarantine Facility for transfer to approved containment laboratories elsewhere should not be excluded, on the condition that containers and transfer procedures conform to protocols established by a panel of experts (e.g., from the Centers for Disease Control and Prevention) in containment.

    Here “approved containment facilities elsewhere” refers principally to the case where a major international partner in the Mars sample return program wishes to establish an independent BSL-4 facility in which to study untreated samples (see Chapter 6).

  • If the samples are shown to be altogether barren of organic matter, to contain no detectable organic carbon compounds and no other evidence of past or present biological activity, untreated aliquots of the samples should be released for study beyond the confines of the Mars Quarantine Facility.



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