Exploring the Interior of Venus with the VERITAS Gravity Science Investigation

The Venus Emissivity, Radio Science, InSAR, Topography And Spectroscopy (VERITAS) Mission is a proposed NASA Discovery mission that will answer key questions about Venus' structure and evolution, essential to understand the evolution of terrestrial planets both within and outside our Solar System. The VERITAS communication subsystem operates in the Ka- and X- band, which enables large data volume to be downlinked and allows highly-accurate coherent radio tracking thanks to a transponder contributed by the Italian Space Agency (ASI). We will present the results of two sets of comprehensive, independent simulations with JPL's MONTE and GSFC's GEODYN to assess with confidence the performance of VERITAS gravity investigation.

VERITAS will determine the gravity field to degree and order >100 globally, a marked improvement over Magellan's uneven spatial resolution, which will permit in combination with the radar-derived topography to resolve subsurface density variations linked to possible continental roots in tesserae and to identify buried topographic features such as impact basins, rift zones, or tessera inliers. The uniform resolution is also important to conduct robust spectral analysis and determine elastic thickness from admittance and coherence to constrain thermal evolution. VERITAS will also measure the tidal Love number (±0.001) and its phase lag (±0.1°), as well as the Venus pole position with high accuracy, allowing the pole precision to be measured (±20 arcsec/cy), and thus the moment of inertia factor (±0.002). These geophysical parameters are directly related to the state of the deep interior of Venus, and together offer an opportunity to accurately constrain core size, state, and mantle viscosity.