Earth contamination free sample acquisition from an Earth contaminated spacecraft

The paper describes the first step in the feasibility demonstration of a novel low cost Mars Sample Return Sample Transfer Sequence (STS) that does not require cleaning and sterilization of the entire spacecraft. The proposed STS relies on ability to collect (and in the future deliver to Earth) Earth-contamination-free samples from a spacecraft that was cleaned only to the levels achieved on Pathfinder. The latter satisfied Planetary Protection Category IVa (PP IVa) requirements, typical for a landed spacecraft. Ability to sterilize or clean to sterility the entire spacecraft is a risky and poorly developed technology. The proposed sample collection approach relies on mechanical removal of the contaminated surface layer and collection of a clean sample from the cleared area. Verification procedures for this approach require probabilistic assessments of the sample contamination levels for a given level of surface contamination.