Assessment of geologic mapping capability of the Italian PRISMA hyperspectral data as a precursor to NASAs Surface Biology and Geology (SBG) mission

Use of hyperspectral remote sensing data for mineral mapping is limited by the lack of global data. NASAs Hyperion instrument was the first to demonstrate that an imaging spectrometer could be operated from space. In 2019, the Italian Space Agency launched the PRISMA VSWIR hyperspectral scanner, and made data available to the research community. PRISMA is a sampling (not global) mission, with 30 m pixels and 30 km swath width. It is an excellent precursor for NASAs Surface Biology and Geology (SBG) mission, that will be the first VSWIR hyperspectral scanner with global, repeating coverage. We compared mineral mapping capability of PRISMA to Hyperion and AVIRIS data, for the Cuprite mining district in Nevada, USA. This area has been used for over 40 years as a test site for numerous airborne and spaceborne instruments. We extracted reflectances from a playa to evaluate the SNR. Hyperion had the lowest SNR (35), and PRISMA had the highest (110). We extracted average reflectance spectra for three primary alteration minerals: alunite, kaolinite, and silica (opalized); and buddingtonite. Compared to lab spectra, the PRISMA and AVIRIS spectra accurately displayed the characteristic absorption features in sufficient detail for identification. Hyperion spectra were noisier, critical absorption features were lacking. We applied Spectral Angle Mapper analysis to the three data sets and created abundance maps. To assess accuracy, we used the detailed mineralogical map produced by Swayze et al. (2014). We were unable to find the small buddingtonite outcrop in the Hyperion data, due to its low SNR. The distributions of alunite, kaolinite, and opalized were accurately represented in the AVIRIS and PRISMA SAM. The Hyperion SAM images were less accurate, showing only the areas with highest mineral abundances. Our analyses of PRISMA data indicate that SBG will set a new standard for space-based hyperspectral imaging. SBGs unprecedented global coverage will open up the entire land surface for surface composition mapping. Any discipline that depends on accurate depiction of the composition of the land surface will have access to repeating, near laboratory-quality spectroscopic VSWIR measurements. © California Institute of Technology, Jet Propulsion Laboratory. Government sponsorship acknowledged.