Hickey, A.A.HickeyDurante, D.D.DuranteIess, L.L.IessPlainaki, C.C.PlainakiMILILLO, AnnaAnnaMILILLOMURA, AlessandroAlessandroMURA2023-04-262023-04-262019http://hdl.handle.net/20.500.12386/34114Orbit determination allows us to determine a spacecraft’s position, velocity, and dynamical model parameters that directly affect a spacecraft’s trajectory, such as gravity field coefficients, which relate to the interior structure of a planetary body, and tidal forces. In addition, when a spacecraft experiences substantial drag in the presence of an exosphere/atmosphere, the density profile may be estimated. This work presents an analysis of two cases where atmospheric drag has effects on the orbit and gravity measurements in planetary missions: Cassini, the mission to Saturn’s system which ended with a plunge into the planet in 2017, and JUICE, the future mission to Jupiter’s icy moons which will include an insertion into a circular, polar orbit around Ganymede. For Saturn, we have estimated a vertical atmospheric density profile which we have compared with in-situ measurements taken by Cassini’s INMS (Ion and Neutral Mass Spectrometer). For Ganymede, we find that the exosphere may be dense enough to affect JUICE’s trajectory around the moon.ELETTRONICOenConference paperhttps://issfd.org/ISSFD_2019/ISSFD_2019_AIAC18_Hickey-Anne.pdfhttps://search.informit.org/doi/book/10.3316/informit.9781925627213FIS/05 - ASTRONOMIA E ASTROFISICA