Laboratory VNIR emissivity of Venus analog rocks and the VEM on VERITAS and the VenSpec-M on EnVision calibration and data verification plan

Abstract

The Venus Emissivity Mapper (VEM) and the VenSpec-M on the NASA VERITAS and ESA EnVision missions, respectively, are multi-spectral imaging systems designed specifically for mapping the surface of Venus using near-infrared atmospheric windows around 1 μm. VEM/VenSpec- M will provide the first global map of rock types on the surface of Venus as well as constant monitoring for volcanic activity at global (VERITAS) and regional/local (EnVision) scales. The VEM/VenSpec- M verification plan ensures accurate performance and science return of the instrument and includes on-ground and in-flight instrument calibrations as well as supporting laboratory measurements for calibration and scientific data analysis. Pre-flight calibrations encompass geometric, spectral, and radiometric calibrations based on the MERTIS (on BepiColombo) calibration campaign and pipeline. Laboratory work involves the creation of spectral libraries of increasing complexity by measuring the emissivity of Venus analogs under Venus surface conditions. These data will distinguish between basalt and felsic rock types on the Venus surface and may enable the identification of intermediate compositions based on iron content. Data analysis uses machine learning models for classification between basalt and felsic rocks and regression to predict FeO content using laboratory calibration data. The data verification plan outlined here not only provides fundamental data needed for VEM/VenSpec-M, but can also be adapted to create data products suitable for calibration of the VenDi (Venus Descent Imager) instrument on the DAVINCI mission. Such use of an integrated calibration plan will benefit all three missions and produce coordinated results that can be directly compared.