Status update of NASAs assessment of the biological contamination threat of crewed mars surface missions.

As we prepare for a future first mission to Mars with a human crew, the United States, under the Outer Space Treaty of 1967, has an obligation to protect against harmful contamination of the red planet and to protect the Earth from the potential harmful effects of material brought from Mars. In previous years NASA has partnered with the Committee on Space Research (COSPAR), the European Space Agency (ESA), the Japanese Aerospace Exploration Agency (JAXA) and other space exploration organizations to conduct a series of workshops on identifying knowledge gaps for protecting Mars from Earth microorganisms during such a crewed mission, and for protecting Earth from a potential Martian biosphere, should it exist. The current international planetary protection consensus policy (COSPAR, 2024) only has high-level guidance for crewed missions thus continuing conversations are needed to further define specific requirements for implementing a crewed missions to Mars. In this paper, we are surveying the biological contamination tradespace to capture and understand the scope of terrestrial microbiology present on a crewed Mars mission. This is a first step to ensure we can manage the harmful biological contamination threat to a putative Martian biosphere and that terrestrial biological contamination will be controlled. Additionally, we are working towards developing a common understanding and basis of assessment of the contamination thresholds that can be used to describe "how much is too much" from a policy point of view. Specifically, we are providing estimates of what the biological contamination will be for a 30 sol stay with two crew members on the surface of Mars. The study is to identify the sources and estimate the scale of biological contamination a human mission might bring to the surface of Mars, and to identify where we can potentially reduce or mitigate that contamination. This work does not consider backward contamination to Earth from a crewed mission to Mars, or orbital contamination in any detail. The architecture that we studied is described in HEOMD 415 (Hoffman 2022) which details a "small footprint" mission that would consist of 4 crew members for the trip to Mars, with 2 crew staying in orbit and 2 going to the surface of Mars in a 3 × 25Ton lander configuration, as well as a variant that used a single, larger lander concept. In these concepts, crew would stay in a pressurized rover and not a fixed habitat. The crew would be on the surface for approximately 30 sols in this minimum mission. It is important to note that there is no designated NASA architecture for a crewed mission to Mars and that the one we used is already in the process of being further updated.