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Abstract EANA2024-125


Science outcomes of the report of the Expert Committee for the Large-class mission in ESA’s Voyage 2050 plan covering the science theme “Moons of the Giant Planets”

Martins, Z.(1); Bunce, E.J.(2); Grasset, O.(3); Hamp, R.(4); Jones, G. H.(5,6); Le Gall, A.(7); Lucchetti, A.(8); Postberg, F.(9); Prieto-Ballesteros, O.(10); Roth, L.(11); Tortora, P.(12); and Vorburger, A.(13)
(1) Centro de Química Estrutural, Institute of Molecular Sciences and Department of Chemical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal (2) School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK (3) Nantes Université, Présidence de l'université 1, quai de Tourville, BP 13522, 44035 Nantes Cedex, France (4) The Open University, Walton Hall, Kents Hill, Milton Keynes, MK7 6AA, UK (5) UCL Mullard Space Science Laboratory, Holmbury St. Mary Dorking, Surrey, RH5 6NT, UK (6) International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland (7) LATMOS/IPSL, UVSQ Université Paris‐Saclay, Sorbonne Université, CNRS, 11 Boulevard D’Alembert 78, 280 Guyancourt, France. (8) INAF-OAPD Astronomical Observatory of Padova, Vicolo dell'Osservatorio, 5, 35122, Padova, Italy (9) Freie Universitaet Berlin, Institute of Geological Sciences, Malteserstrasse 74 - 100, 12249 Berlin, Germany (10) Centro de Astrobiología-CSIC-INTA, Instituto Nacional de Técnica Aeroespacial (INTA), Carretera de Ajalvir km. 4, 28850 Torrejón de Ardoz, Spain (11) Space and Plasma Physics, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden (12) Alma Mater Studiorum - Università di Bologna, Department of Industrial Engineering, Via Fontanelle 40, I-47121 Forlì (FC), Italy (13) Space Research & Planetary Sciences, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland


Following the final recommendations from the Voyage 2050 Senior Committee Report, in December 2021, the European Space Agency (ESA) appointed an Expert Committee for the Large-class (L4) mission covering the science theme “Moons of the Giant Planets”.

The Expert Committee has considered how a new ESA L4 mission could address priority topics such as habitability, prebiotic chemistry, and biosignatures, providing new knowledge significantly beyond any previous space missions. The Expert Committee has considered planetary probe missions to one or more of the moons of Jupiter and Saturn, with a targeted launch date in the early 2040s, and different possible mission scenarios that would ensure the L4 mission to deliver a transformational scientific return. Several aspects of the habitability of ocean worlds need to be addressed by future space mission, including 1) The issue of habitability of ocean worlds and the interaction between the surface and the interior; 2) The issue of habitability of oceans worlds and the interaction with the external environments; and 3) The identification of prebiotic chemistry and the search for biosignatures on ocean worlds.

Based on these three themes (i.e., their relevance), and considering whether planned space missions to the moons of giant planets address the proposed science objectives , the Expert Committee identified Saturn’s moon Enceladus as the most interesting target, followed by Titan in the same system, and Jupiter’s moon Europa. In order for the mission to be really transformational, it should include an in-situ sample acquisition, either using a lander or by sampling ejecta during plume flythroughs to access fresh material from the subsurface.  An Enceladus south polar lander with an orbiter and plume sampling system would be the optimum candidate for the L4 mission. This would be achievable by a dual launch configuration (A64+A64), with Near-Earth rendezvous prior to escape. For Titan, the Expert Committee has suggested the investigation of lake sediments, a very different type of landing location with respect to past or selected missions. In order to meet the goals for Titan, the mission should include a Titan orbiter, which seems currently challenging according to performed studies. Additionally, a reconnaissance phase and an autonomous hazard detection and avoidance system would be required to ensure targeted and safe landings on selected terrains. Furthermore, an additional tour of other moons considered to potentially host a liquid subsurface should be performed, e.g., Mimas.

Any of the above L4 mission concepts will dramatically improve our understanding of the habitability and the detection of biosignatures on our solar system, and would guarantee that ESA would have a leadership position in the science theme “Moons of the Giant Planets”.

Acknowledgements.

We thank the ESA L4 Study Team for useful discussions and support.