The rover sample cache system: Planetary protection for sample return missions

NASA Ames Research Center has designed and developed a Rover Sample Cache System (RSCS) for use on the Mars Science Laboratory. The RSCS is a small container that can accommodate rock samples, and be picked up by a future sample return mission. This hardware is the first NASA has built that could make a round trip to Mars. Although the decision has been made to not fly the RSCS, its development illustrates important Planetary Protection considerations. Policies for sample return missions have not yet been fully vetted by the international community, and will be the subject of future discussions at COSPAR. In this paper, we describe the development of new protocols and requirements for the RSCS. Testing consisted of two main components: the NASA Standard Assay of all mated and exposed surfaces, and the collection of samples for a DNA sequence-based genetic inventory of all microorganisms sampled from the RSCS and related assembly environments.