Future Missions related to the determination of the elemental and isotopic composition of Earth, Moon and the terrestrial planets Iannis Dandouras, Michel Blanc, Luca Fossati, Mikhail Gerasimov, Eike Guenther, Kristina Kislyakova, Helmut Lammer, Yangting Lin, Bernard Marty, Christian Mazelle, et al. To cite this version: Iannis Dandouras, Michel Blanc, Luca Fossati, Mikhail Gerasimov, Eike Guenther, et al.. Future Missions related to the determination of the elemental and isotopic composition of Earth, Moon and the terrestrial planets. Journal Space Science Reviews, 2020, Space Science Reviews, 10.1007/s11214- 020-00736-0. hal-02930740 HAL Id: hal-02930740 https://hal.archives-ouvertes.fr/hal-02930740 Submitted on 4 Sep 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Future Missions 1 Chapter 12 2 3 Future Missions related to the determination of the elemental and isotopic 4 composition of Earth, Moon and the terrestrial planets 5 1 1 2 3 6 Iannis Dandouras , Michel Blanc , Luca Fossati , Mikhail Gerasimov , Eike W. 4 2,5 2 6 7 Guenther , Kristina G. Kislyakova , Helmut Lammer , Yangting Lin , Bernard 7 1 8 2 9 8 Marty , Christian Mazelle , Sarah Rugheimer , Manuel Scherf , Christophe Sotin , 2,10 11 12 13 9 Laurenz Sproß , Shogo Tachibana , Peter Wurz , Masatoshi Yamauchi 1 10 Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse / CNRS / 11 UPS / CNES, Toulouse, France 2 12 Space Research Institute, Austrian Academy of Sciences, Graz, Austria 3 13 Space Research Institute of RAS (IKI), Moscow, Russia 4 14 Thüringer Landessternwarte Tautenburg, Tautenburg, Germany 5 15 Department of Astrophysics, University of Vienna, Vienna, Austria 6 16 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China 7 17 Nancy Université, Nancy, France 8 18 Department of Physics, Oxford University, Oxford, UK 9 19 Jet Propulsion Laboratory, NASA, Pasadena, CA, USA 10 20 Institute of Physics, University of Graz, Graz, Austria 11 21 Hokkaido University, Sapporo, Japan 12 22 University of Bern, Physikalisches Institut, Bern, Switzerland 13 23 Swedish Institute of Space Physics (IRF), Kiruna, Sweden 24 Corresponding author: Iannis Dandouras ([email protected]) 25 Key Point: 26 • Future missions will strongly contribute to our understanding of planetary evolution 27 1 Future Missions 28 Abstract 29 In this chapter, we review the contribution of space missions to the determination of the 30 elemental and isotopic composition of Earth, Moon and the terrestrial planets, with special 31 emphasis on currently planned and future missions. We show how these missions are going 32 to significantly contribute to, or sometimes revolutionise, our understanding of planetary 33 evolution, from formation to the possible emergence of life. We start with the Earth, which is 34 a unique habitable body with actual life, and that is strongly related to its atmosphere. The 35 new wave of missions to the Moon is then reviewed, which are going to study its formation 36 history, the structure and dynamics of its tenuous exosphere and the interaction of the Moon’s 37 surface and exosphere with the different sources of plasma and radiation of its environment, 38 including the solar wind and the escaping Earth’s upper atmosphere. Missions to study the 39 noble gas atmospheres of the terrestrial planets, Venus and Mars, are then examined. These 40 missions are expected to trace the evolutionary paths of these two noble gas atmospheres, 41 with a special emphasis on understanding the effect of atmospheric escape on the fate of 42 water. Future missions to these planets will be key to help us establishing a comparative view 43 of the evolution of climates and habitability at Earth, Venus and Mars, one of the most 44 important and challenging open questions of planetary science. Finally, as the detection and 45 characterisation of exoplanets is currently revolutionising the scope of planetary science, we 46 review the missions aiming to characterise the internal structure and the atmospheres of these 47 exoplanets. 48 12.1. INTRODUCTION 49 The previous chapters of this topical series presented in considerable detail what we 50 know on the way the evolution of a planet and its atmosphere, from formation to the possible 51 emergence of habitable worlds, influences its elemental, chemical and isotopic composition. 52 Indeed, the chemical and isotopic composition of the different constituents of a planet are 53 shaped by initial conditions such as the composition and activity of its host star (Güdel, 2020) 54 and the structure and composition of the circumstellar nebula out of which it was born 55 (Bermingham et al., 2020). In the course of its evolution, each planetary atmosphere is fed by 56 additional material from its space environment and from the planet’s degassing interior 57 (Stüeken et al., 2020) while a fraction of its atmospheric chemical elements escape to outer 58 space (Lammer et al., 2020a). A quantitative assessment of the effects of these mechanisms 59 can be partly constrained in the chemical and isotopic composition of the different planetary 60 layers, among them its atmosphere, and in the meteorite record (e.g., O’Neil et al., 2020) 61 where they can be most easily measured. These measurements provide constraints on the 62 formation history of Earth, Moon and the terrestrial planets (Lammer et al., 2020b), on the 63 evolution of planetary atmospheres (Avice and Marty, 2020; Stüeken et al., 2020) and on their 64 current composition (Scherf et al., 2020). Last but not least, when life emerges, like on Earth, 65 it also leaves a strong imprint on the planet’s composition (Lloyd et al., 2020). 66 In this article, we review the contribution of space missions to Earth, Moon and the 67 terrestrial planets, to the determination of their elemental and isotopic composition, with 68 special emphasis on currently planned and future missions. We show how these missions are 69 going to strongly contribute to, or sometimes revolutionise, our understanding of planetary 70 evolution, from formation to the possible emergence of life. Our scope is not to provide an 71 exhaustive list of missions, but to highlight some missions to the inner planets of our Solar 72 System addressing these objectives, and then to expand our review to missions aiming to 73 characterise planets around other stars. 2 Future Missions 74 We start this review with missions to the Earth-Moon system (section 12.2). Building 75 on the legacy of Apollo and of several other important missions to the Moon, we review the 76 current plans for a new wave of Moon missions from a broad range of countries and from the 77 public and private spheres. These missions, combining orbiter and lander elements, are aimed 78 at studying the formation history of the Moon, the structure and dynamics of its tenuous 79 exosphere, and the interaction of the Moon’s surface and exosphere with the different sources 80 of plasma and radiation of its environment, including the solar wind and the escaping Earth’s 81 upper atmosphere. We also review the current plans for missions in Earth orbit that will help 82 better quantify the atmospheric losses processes and also their effects on the Earth’s upper 83 atmosphere and magnetosphere. 84 In section 12.3 we review past studies and current plans to use noble gases in the 85 atmospheres of the terrestrial planets, Venus and Mars, to trace the evolutionary paths of 86 these atmospheres, with a special emphasis on understanding the effect of atmospheric escape 87 on the fate of water. Future missions to these planets will be key to help us establish a 88 comparative view of the evolution of climates and habitability at Earth Venus and Mars, one 89 of the most important and challenging open questions of planetary science. In a similar way, 90 past (Messenger) and current (BepiColombo) missions to Mercury are expected to provide a 91 new view of the bulk and exosphere composition of this planet, the only example of a hot 92 close-in terrestrial planet in our Solar System. 93 While remote sensing and in situ measurements are expected to provide new insights 94 into these questions, return of samples of surface, sub-surface and atmospheres to our Earth 95 laboratories is the most promising perspective to write an accurate evolutionary history of 96 terrestrial planets, as illustrated by the outstanding scientific legacy of the Apollo and 97 Lunakhod programs. Future, currently planned sample return missions to the Moon (sections 98 12.2.2.2 and 12.2.2.3) will give us access to the broad diversity of Moon terrains, spanning 99 their different ages. They raise the hope of a far better understanding of the formation history 100 of the Earth-Moon system and of a comprehensive inventory of the Moon’s mineral and 101 water resources. At Mars, sample return is the pillar of future exploration, bearing our hope to 102 detect possible traces of extinct or extant life on the Red Planet (section 12.3.2). Sample 103 return from asteroids and comets, as the currently operating Hayabusa2 and OSIRIS-Rex 104 (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) 105 missions, will in parallel provide unique constraints on the initial composition of the building 106 blocks of terrestrial planets and on their sources of water (section 12.4).