(Georgia Institute of Technology, 2018-03)
Sotin, Christophe; Avice, Guillaume; Baker, John; Freeman, Anthony; Madzunkov, Stojan; Stevenson, Terry; Arora, Nitin; Darrach, M. R.; Lightsey, E. Glenn; Marty, B.
Getting reliable measurements of noble gases in Venus’ atmosphere with a CubeSat-derived mission concept is very challenging. But if feasible it could change how we make this fundamental geochemical measurement in planetary atmospheres and other gaseous environments (e.g., plumes emanating from icy moons or dwarf planets) across the solar system. Venus poses the most urgent and nearby target for such measurements, to fill in a key piece of the puzzle of Venus’ origin, evolution, and divergence from Earth’s geophysical history. Understanding Venus’ geophysical evolution is also key to interpreting observations of “Earth-like” exoplanets in order to assess whether they are Earth-like or Venus-like, which has obvious implications for their habitability potential. Noble gases are tracers of the evolution of planets. They trace processes such as the original supply of volatiles from the solar nebula, delivery of volatiles by asteroids and comets, escape rate of planetary atmospheres, degassing of the interior, and its timing in the planet’s history. However, a major observational missing link in our understanding of Venus’ evolution is the elementary and isotopic pattern of noble gases and stable isotopes in its atmosphere, which remain poorly known [1]. The concentrations of heavy noble gases (Kr, Xe) and their isotopes are mostly unknown, and our knowledge of light noble gases (He, Ne, Ar) is incomplete and imprecise. The Cupid’s Arrow mission concept would measure those quantities below the homopause where gas compounds are well mixed.