Expectations for Backward Planetary Protection Planning During Mars Sample Return Planning

During the current phase of robotic exploration, Mars missions plan to search for evidence of extinct or extant biological activity. The conceptual mission architecture for Mars Sample Return (MSR) must demonstrate robust containment and rigorous control of all unsterilized materials as assurance of no inadvertent harm to Earth's biosphere. Launch of NASA's drilling and caching Mars rover in summer 2020 could potentially be the first step in an extraordinary campaign to bring carefully collected and sealed samples of sedimentary and igneous rocks from Mars to Earth for scientific study. As part of this notional architecture, NASA would launch a sample return platform early as 2026 to land near the area explored by the Mars 2020 rover and ESA would launch separately an Earth Return Orbiter (ERO). A small ESA fetch rover would depart from the platform and drive rapidly to locations where samples tubes have been placed on the ground for retrieval. The fetch rover and/or the Mars 2020 rover could return to the platform, allowing a robotic arm to transfer samples tubes into a sample container on a Mars Ascent Vehicle (MAV). The sample container would be launched and then released by the MAV in Mars orbit where the waiting ERO would capture the container and seal it in a doubled-walled containment canister. Various combinations of sterilization and dust mitigation are under consideration for breaking the chain of contact with putative contaminants. Minimizing the area of surfaces exposed to Martian dust and performing one or more sterilization procedures are key options for compliance with backward planetary protection prior to departure from Mars orbit. Once landed on Earth, entry vehicle inspection followed by additional cleaning and biobarrier deployment would ensure safe handling during transport to a state-of-the-art receiving facility. Herein, we describe NASA and ESAs joint coordination efforts with COSPAR to engage disciplinary experts across academic, regulatory, and industrial organizations to discuss current technology for life detection and sample safety protocols for handling and studying Mars materials on Earth.