• The potential for large-scale effects on the Earth's environment by any returned entity released to the environment;

• The status of technological measures that could be taken on a mission to prevent the inadvertent release of a returned sample into the Earth's biosphere; and

• The criteria for intentional sample release, taking note of current and anticipated regulatory frameworks.

In addition to these points, we also request that you assess the extent to which our increasing capabilities for studying the Earth's microbial inhabitants might appropriately be used to alter or improve implementation of the Mars sample return planetary protection requirements recommended in the 1997 report.

In order for NASA to include the results of this study activity during planning for Mars Sample Return in coordination with the international working group IMARS, it would be highly desirable to receive an interim report by October 3, 2008, and a final report by May 29, 2009.

I would like to request that the NRC submit a plan for execution of the study described herein. Once agreement on the scope, cost, and schedule for the proposed study has been achieved, the Contracting Officer will issue a task order for implementation. Dr. Catharine A. Conley, Planetary Protection Officer, will be the technical point of contact for this effort, and may be reached at cassie.conley@nasa.gov or (202) 358-3912.