SAMPLES AND NOTIONAL CACHES FROM JEZERO CRATER AND BEYOND FOR MARS SAMPLE RETURN

The NASA Mars 2020 Perseverance rover will collect a suite of scientifically compelling samples for return to Earth. On the basis of orbital data, the Mars 2020 science team identified two notional caches to capture (1) the geology of Jezero crater during the prime mission and (2) the ancient crust outside of Jezero crater during a possible extended mission.

In the prime mission, samples will come from the Late Noachian to Early Hesperian crater floor, rim, delta, marginal deposits, and regolith. Of particular interest are materials deposited under past habitable conditions with high biosignature preservation potential, such as siliciclastic and chemical sedimentary rocks. Samples for this notional cache address the questions: 1) What habitable niches existed at Jezero, when did they exist, and are associated biosignatures/organics preserved?; 2) When did fluviolacustrine activity occur and what was the source region?; 3) Can Jezero lithologies calibrate Mars’ crater chronology?; 4) What were the origin and alteration history of regional Noachian crust?; and 5) How can these lithologies inform Mars’ climate/hydrologic evolution? Sampling is underway on crater floor units.

Perseverance would explore the Nili Planum region outside Jezero crater during an extended mission. Nili Planum is distinct from the Jezero basin in that it comprises diverse Early- or Pre-Noachian rocks. This cache may include basement rocks, megabreccia, fracture-filing veins, olivine- and carbonate-bearing rocks, and mafic cap rock. These samples extend the scientific value by addressing four additional questions: 6) What characteristics defined Mars’ early planetary evolution and habitability?; 7) How long did the martian dynamo persist?; 8) How do ancient bedrock and/or ejecta enable calibration of Mars’ crater chronology?; and 9) What were the local/regional effects of the Isidis impact?

The caches described are notional and may be modified with ongoing investigation. They also align with community priorities for Mars exploration, addressing geologic diversity, potential biologic activity on Mars, planetary evolution (e.g., magnetic field, atmosphere, and climate), volatiles, and human health hazards.

Acknowledgement: The planning and sampling described was performed by the entire Mars 2020 Science and Engineering teams.