Comparing the Emissivity Response of Venus Analogs Under Venus Surface Simulated Conditions in Preparation for the Analysis of VEM/VENSPEC-M Data

Kurzfassung

Surface rocks on Venus are subjected to a dense atmosphere predominantly composed of CO2 (around 96.5%) and N2 (about 3.5%), along with small quantities of other gases, including H2O and various sulfur compounds (e.g., SO2 and H2SO4). Temperatures are ~460°C and pressures are approximately 90 times greater than those on Earth. Understanding the surface - atmosphere interactions on Venus is critical for interpreting data from the NASA VERITAS and DAVINCI and the ESA EnVision missions. Collaborative research between the Planetary Spectroscopy Laboratory (PSL) at the German Aerospace Center (DLR) in Berlin and the Hot Environments Laboratory (HEL) at NASA Goddard Space Flight Center (GSFC) focuses on comparing the emissivity responses of altered versus unaltered Venus surface analogs in the 1 μm spectral region. We seek to understand how rocks on Venus' surface may chemically interact with the atmosphere. The 1 μm spectral region used for these measurements corresponds to windows in the spectrum of CO2 in Venus’ thick cloud cover. Remote sensing is therefore possible despite the thick Venusian atmosphere that hinders surface observations at other wavelengths [1, 2]. The Venus Emissivity Mapper (VEM) onboard VERITAS and the VenSpec-M instrument on EnVision will observe Venus using 14 spectral bands: six surface bands covering five atmospheric windows between 0.86 and 1.18 μm, two water vapor bands, three cloud bands and three background bands [3]. Meanwhile, the DAVINCI Venus Imaging System for Observational Reconnaissance (VISOR) camera will measure thermal emission during flybys using two surface bands and one water band. Consequently, spectra must be measured in terms of emissivity at Venus surface temperatures