Titan Gravity and Tidal Love Number Simulation: Synthetic Observations of Cassini and Tianwen Titan Orbits

Abstract

This study evaluates how a future Tianwen-Titan orbiter could improve Titan gravity-field and tidal Love-number recovery when combined with a Cassini-based simulated tracking baseline. A multi-arc covariance framework implemented with the Tudat astrodynamics toolbox is used to compare two representative orbiter geometries: a 40° mid-inclination orbit for repeated low- and mid-latitude sampling and a 90° polar orbit for global latitudinal coverage. For periapsis altitudes of 1500 and 1000 km, the lower-altitude cases extend the recoverable gravity spectrum from 10°–11° to 12°–15°. At 1500 km, the 40° configuration reduces the formal uncertainty of k₂ from about 0.067–0.070 in the Cassini baseline to approximately 0.002 and improves C₂₂ to about 0.0025 × 10^–6. The 90° configuration more strongly constrains odd zonal harmonics, reducing J₃ and J₅ uncertainties by factors of about 10 and 24. These results indicate that mid-inclination and polar orbiters provide complementary sensitivity for future Titan gravity science and interior structure interpretation.