Optimizing ExoMars 2022 Rover Remote Sensing Multispectral Science:
Cross-Rover Comparison using Laboratory and Orbital Data
Abstract
Multispectral imaging instruments have been core payload components of
Mars lander and rover missions for several decades. In order to place
into context the future performance of the ExoMars 2022 Rosalind
Franklin rover, we have carried out a detailed analysis of the spectral
performance of three visible and near-infrared (VNIR) multispectral
instruments. We have determined the root mean square error (RMSE)
between the expected multispectral sampling of the instruments and
high-resolution spectral reflectance data, using both laboratory
spectral libraries and Mars orbital hyperspectral data. ExoMars
Panoramic Camera (PanCam) and Mars2020 Perseverance Mastcam-Z
instruments have similar values of RMSE, and are consistently lower than
for Mars Science Laboratory Mastcam, across both laboratory and orbital
remote sensing data sets. The performance across mineral groups is
similar across all instruments, with the lowest RMSE values for
hematite, basalt, and basaltic soil. Minerals with broader, or absent,
absorption features in these visible wavelengths, such as olivine,
saponite, and vermiculite have overall larger RMSE values. Instrument
RMSE as a function of filter wavelength and bandwidth suggests that
spectral parameters that use shorter wavelengths are likely to perform
better. Our simulations of the spectral performance of the PanCam
instrument will allow the future use of targeted filter selection during
ExoMars 2022 Rosalind Franklin operations on Mars.