Laboratory for Particle Physics (LTP)

LTP Colloquium

Searching for Signs of Life with the ExoMars Rover

Thursday, December 5, 2019, 16:00
WHGA Auditorium

Jorge Vago, ESA

The ExoMars 2020 launch period opens on 26 July 2020 and extends until 11 August. On 19 March 2021 the mission will deliver two science elements to the martian surface: (1) a lander instrumented to conduct environment and geophysics measurements, and (2) a 310-kg rover tasked with conducting a search for signs of life [1].

The rover-named after Rosalind Franklin-will use a drill to collect samples from outcrops and at depth. The drill can reach down to 2 m below the surface; such depth range has never been probed on Mars before. ExoMars' subsurface sampling capability will provide the best chance yet to access and analyse sedimentary deposits, possibly containing molecular biosignatures, that may have been shielded from the ravages of ionizing radiation prevailing at the surface.

The rover's Pasteur payload includes: panoramic instruments (PanCam [2] wide-angle and high-resolution cameras; ISEM [3], an infrared spectrometer; WISDOM [4], a ground-penetrating radar; and ADRON [5], a neutron detector); a subsurface drill to acquire samples; contact instruments for studying rocks and collected material (CLUPI [6], a close-up imager; and Ma_MISS [7], an infrared spectrometer in the drill head); a Sample Preparation and Distribution System (SPDS); and the analytical laboratory, the latter including MicrOmega [8], a visual and infrared imaging spectrometer; RLS [9], a Raman spectrometer; and MOMA [10], a Laser-Desorption, Thermal-Volatilization, Derivatization, Gas Chromatograph Mass Spectrometer (LD + Der-TV GCMS).

The ExoMars 2020 mission will land at Oxia Planum, an ancient location interpreted to possess strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). Oxia Planum is situated on the eastern margin of the Chryse basin, along the martian dichotomy border, and at the outlet of the Coogoon Valles system. At present, the coordinates for the nominal touchdown location are 18.159ºN, 24.334ºW. The approximately 100 km x 9 km dispersion ellipse lies in the lower part of a wide basin, where extensive exposures of Fe/Mg-phyllosilicates (> 80% of the ellipse surface area) have been detected with OMEGA and CRISM hyperspectral and multispectral data. The Fe/Mg-rich clay detections are associated with early/middle- to late-Noachian layered rocks (with layering thickness ranging from a few meters to < 1 m for several tens of meters). They may represent the southwestern expansion (lowest member) of the Mawrth Vallis clay-rich deposits, pointing to a geographically extended aqueous alteration environment, perhaps an ocean.

No previous mission will have landed at such an ancient location. The Oxia Planum clay deposits are dated at 4.1 Ga, from the epoch when Mars' surface was crisscrossed by plentiful liquid water systems. The oldest landing site so far has been that of Curiosity (3.6 Ga).

The ExoMars mission will be capable of securing many firsts: (1) the oldest site investigated on Mars, (2) the first exploration of the martian subsurface, (3) the most accurate geological and organic composition determination so far, and (4) the best chance yet to make (potential) biosignature detections on another planet.


[1] Vago, J. L., et al. (2017) Astrobiology 17(6-7), 471-510, 10.1089/ast.2016.1533
[2] Coates, A. J., et al. (2017) Astrobiology 17(6-7), 511-541, 10.1089/ast.2016.1548
[3] Korablev, O. I., et al. (2017) Astrobiology 17(6-7), 511-541, 10.1089/ast.2016.1543
[4] Ciarletti, V., et al. (2017) Astrobiology 17(6-7), 565-584, 10.1089/ast.2016.1532
[5] Mitrofanov, I. G., et al. (2017) Astrobiology 17(6-7), 585-594, 10.1089/ast.2016.1566
[6] Josset, J.-L., et al. (2017) Astrobiology 17(6-7), 595-611, 10.1089/ast.2016.1546
[7] De Sanctis, M. C., et al. (2017) Astrobiology 17(6-7), 612-620, 10.1089/ast.2016.1541
[8] Bibring, J.-P., et al. (2017) Astrobiology 17(6-7), 621-626, 10.1089/ast.2016.1642
[9] Rull, F., et al. (2017) Astrobiology 17(6-7), 627-654, 10.1089/ast.2016.1567
[10] Goesmann, F., et al. (2017) Astrobiology 17(6-7), 655-685, 10.1089/ast.2016.1551