Influence of low orbit design and strategies for gravity field recovery of Europa

The gravity field of the Solar System celestial bodies is generally estimated within orbit determination process probes visiting them. Low altitude, high inclination and near circular orbits are best suited for this purpose. As part a global characterization effort Jovian moon Europa, we studied influence multiple orbital parameters configurations on recovery its parameters. We made use Repetitive Ground Track Orbits (RGTO), allowing proper definition ground track coverage surface which essential to study impact coverage. results presented here rely closed-loop simulations performed using development version Bernese GNSS Software with planetary geodesy capabilities. simulate realistic range-rate observables (2-way Doppler X-band, σ ​= ​0.10 ​mm/s) from different considered over total mission duration 3 months. These observations then used reconstruct estimate coefficients in terms spherical harmonic k2 Love number. systematically compare solutions based input quantify their process, great importance future designs. Our case scenario shows that can be up degree order 72 after months polar at 100 ​km Europa's surface. Different strategies also discussed when starting very poor priori knowledge field, as it Galileans moons. propose evaluate two approaches by either pseudo-stochastic pulses (i.e., instantaneous velocity changes) cope large model deficiencies, or co-estimating low-degree bootstrap estimation process.