Abstract

NASA's Mars 2020 mission is the first step in a potential campaign to bring martian samples back to Earth for detailed study. After launch in the summer of 2020, the Mars 2020 rover will land in Jezero Crater on February 18, 2021. This landing site was selected for its compelling evidence for ancient habitability: sometime in the late Noachian or early Hesperian (i.e., > ~3.5 billion years ago), the crater hosted a ~400 meter deep, 40 km diameter, open-system lake in which a now well-exposed delta system was deposited. In its one Mars year (686 Earth days) prime mission, the Curiosity-heritage Mars 2020 rover will explore the delta, associated fluvio-lacustrine mudstone and sandstone deposits, an enigmatic magnesium carbonate lithology, and possible volcanics. In addition to multiple high-resolution cameras, the rover carries instruments to characterize chemistry, mineralogy, and structure both at the outcrop scale and at the microscale. These observations will be used to interpret the geologic setting and habitability potential of the site, and to seek possible evidence of past microbial life.

Identification, collection, and documentation of rock and regolith samples for possible return to Earth by future missions are central objectives of the Mars 2020 mission. High priority samples will be those with the greatest potential to have once hosted martian life and to answer key questions about the geology and environment of Mars and its evolution as a planet. Rock cores ~1.3 cm in diameter and ~6 cm long (~15 grams) will be drilled from surface outcrop directly into individual ultraclean sample tubes. Unconsolidated samples will be obtained by cascading grains into a sample tube inserted into sand, dust, or regolith. After collection, sample tubes will immediately be inspected, hermetically sealed, and stored on board the rover. The rover carries 38 sample tubes that can be used for rock or regolith, and 5 tubes designed for blank characterization. Of these, approximately 30 (samples + blanks) are considered likely to be returned to Earth in the future, with the remainder allowing for collection failures and for scientific prioritization. The Mars 2020 rover will ultimately deposit all sample tubes on the surface of Mars, leaving retrieval and return of the highest value tubes up to a possible future mission. During the Mars 2020 surface mission, the site(s) at which samples will be deposited will be chosen for ease of access/relocation and to minimize dust cover. Deposited tubes are designed to remain at temperatures <20^oC at Jezero, and to survive at least 50 years on the surface and in transit to Earth.