Sampling Mars: Geologic Context and Preliminary Characterization of Samples Collected by the NASA Mars 2020 Perseverance Rover Mission
The NASA Mars 2020 Perseverance Rover Mission has collected samples of rock, regolith, and atmosphere within the Noachian-aged Jezero Crater, once the site of a delta-lake system with a high potential for habitability and biosignature preservation.
Between sols 109 and 1,088 of the mission, 27 sample tubes have been sealed, including witness tubes. Each sealed sample tube has been collected along with detailed documentation provided by the Perseverance instrument payload, preserving geological and environmental context.
Samples representative of the stratigraphy within each of four campaigns have been collected: samples from the Crater Floor Campaign represent a suite of potentially petrogenetically related igneous rocks displaying variable degrees of aqueous alteration; samples from the Fan Front record fluvial to deltaic sediments formed by the transport and deposition of materials from the Jezero watershed; regolith samples from the Fan Front preserve material possibly representative of global dust as well as diverse, locally derived clasts; Upper Fan samples record the latest stages of aqueous activity within Jezero; and samples from the Margin Campaign preserve lacustrine, littoral, or possibly igneous processes that may have occurred early in the history of the crater.
Along with anticipated samples from the older rocks within the rim of Jezero Crater, Perseverance promises to deliver a suite of samples preserving a diversity of formation environments and ages.
Upon return to Earth and analysis in terrestrial laboratories, these samples would address longstanding questions pertaining to the geologic evolution of Mars, its habitability, and the potential for life outside the Earth.
Images showing the local contexts of Crater Floor samples: (A) 2 to 3 m tall cliff exposures of widespread Máaz formation that locally define the NW-SE trending Artuby Ridge. Kodiak mesa sediments that lie stratigraphically above can be seen in the distance. Boundary with southern edge of Séítah formation lies to the Right side of image. (B) Layering in lower Máaz formation outcrops near southern and eastern side of Séítah. Bouldery, crater-retaining, upper Máaz formation outcrops can be seen in the distance. (C) Tabular ~10 cm thick beds of Séítah formation (Left) grade into more massive, but still locally layered Séítah formation outcrops (Right). — PNAS via PubMed
A primary goal of the NASA Mars 2020 Perseverance rover mission is to select, acquire, and document a scientifically return-worthy collection of martian samples for return to Earth by future missions (1). To achieve this task, the rover is equipped with an integrated suite of science instruments that operate together as part of a mobile sampling platform. Data from remote sensing instruments mounted on a pan/tilt mast and proximity instruments mounted on a robotic arm provide detailed contextual information for each sample (Materials and Methods).
Mars Sample Return (MSR) has been a high priority of the scientific community for decades (McSween, (2); McCubbin, (3)). Detailed analyses in Earth-based laboratories of carefully documented martian samples collected from regions with known geologic contexts will be essential for addressing the highest-priority science questions relating to Mars (4). These questions include those about the geologic history of Mars, particularly the role of water, the evolution of volatiles and climate on Mars, the timeline of planetary scale processes, and the potential biological history of Mars (5).
Perseverance is currently exploring the Noachian-aged Jezero Crater, once the site of a delta-lake system with a high potential for habitability and biosignature preservation. The rover carried 38 identical sample tubes designed for rock core or regolith samples and five witness tube assemblies (“witness blanks”) for characterizing contamination from the rover. At the time of writing, 24 of 38 sample tubes have been sealed, as have 3 of the witness tubes (Table 1). Of these, nine sample tubes (seven containing rock cores, one containing regolith, and one filled with Mars atmosphere) and 1 witness tube have been deposited at the Three Forks depot in Jezero Crater, while the rest are being carried onboard Perseverance. The orientations of all rock core samples have been estimated relative to martian geographic coordinates to enable their records of geological and geophysical processes to be oriented at the time they formed and/or were altered (Weiss et al. (6)).
Sampling Mars: Geologic context and preliminary characterization of samples collected by the NASA Mars 2020 Perseverance Rover Mission, PNAS via PubMed (open access)
Astrobiology
