Mapping Venus’s Gravity Field with the VERITAS Mission

Abstract

The Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy (VERITAS) mission, selected by the NASA Discovery program in 2021, addresses crucial scientific questions about Venus’s evolution, structure, and past and ongoing geological processes. The high-resolution mapping of the gravity field of the planet will give an essential contribution to meet the science objectives of the mission and to further our understanding of Venus. The VERITAS gravity science experiment will enable a gravity map of the planet with substantially higher and more uniform spatial resolution with respect to Magellan. This is achieved thanks to the near-polar, near-circular, lowaltitude orbit (~220 km), and the state-of-the-art quality of Doppler tracking data, collected from two separate and coherent radio links at X and Ka band. Our numerical simulations show that the VERITAS gravity science experiment can robustly fulfill the scientific requirements, achieving a gravity field spatial resolution ranging from 85 to 120 km. Across 90% of the planet, a spatial resolution better than 106 km is expected. Additionally, VERITAS can retrieve crucial parameters required to derive the tidal response and rotational state of Venus, thereby improving our understanding of the planet’s interior structure.