Mars Sample Return Campaign, the science opportunity and challenge.

The currently envisioned Mars Sample Return (MSR) Campaign is one of the most ambitious planetary exploration undertakings ever attempted. Scientifically selected samples collected by NASA's Mars 2020 mission would be returned to Earth through the joint efforts of the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). Upon delivery to Earth, the samples would be made available to the international science community to conduct investigations and address some of the most fundamental questions about the formation and evolution of the solar system and potentially the origins of life. The Mars Sample Return (MSR) Campaign must meet a series of technical and scientific achievements to be successful, including the challenges of maintaining and providing samples in pristine condition for study while maintaining biological containment until the samples can be safely distributed. Updates to the MSR architecture and plans for processing the samples, including a timeline and science opportunities will be discussed. Background What benefits are there to samples from Mars? Our current knowledge of Mars has been limited by spacecraft capability, including limitations to what can be observed from orbit and constraints on the spacecrafts' ability to manipulate and measure martian surface material. We have learned much from Mars meteorites, but they provide a myopic view of Mars' history given the limited types of samples which survive the ejection process and further hampered by the lack of sample context. Even though orbital and in-situ exploration has been insightful, these results also highlight the additional value that would come from narrowing the spatial focus of our observations, being able to manipulate the sample, and widening the diversity of instrumentation, all of which would be possible with samples from Mars on Earth. For example, we have a much better understanding of the evolution of Mars at the planetary scale - Mars was habitable - and yet we have not made definitive progress in understanding if Mars ever had life. In addition, the nature of the dust and regolith remain a knowledge gap for human exploration that could be critical to design mechanical resilience and understand human health risks. How will sample return be accomplished? The technical approach to mitigate the complexity and risks of sample return were proposed as an architecture referred to as "3 + 1", alluding to three flight mission segments to acquire and return the samples, and one ''ground segment'' to receive and investigate the samples on Earth. A key principle of the 3 + 1 architecture was the intervals between the major segments provide safe and stable states to minimize timing risk associated with the sequential nature of the campaign. With this campaign architecture, it was possible land the Perseverance rover and to begin collecting samples (see Farley, 2021) without knowing the full details of the other campaign segments. The plan for the 2nd flight segment is the landed ESA Sample Fetch Rover to retrieve samples and deliver to a NASA Mars Ascent Vehicle for transport of the samples from surface to orbit around Mars The 3rd flight segment, the ESA Earth Return Orbiter Mission, would capture the samples' container in orbit and bring them safely to Earth. The "+1" ground segment is still in early planning system trades to safely maximize the science opportunities of the samples. Disclaimer: The decision to implement Mars Sample Return will not be finalized until NASA's completion of the National Environmental Policy Act (NEPA) process. This document is being made available for planning and information purposes only. References: Farley, K.A., Williford, K.H., Stack, K.M. et al. Mars 2020 Mission Overview. Space Sci Rev 216, 142 (2020). https://doi.org/10.1007/s11214-020-00762-y