THE MARS EXPLORATION ROVERS PLANETARY DATA SYSTEM ARCHIVE OF PANCAM PHOTOMETRY QUBS

The Pancam multispectral visible/near-infrared stereo imaging systems on the Mars Exploration Rovers (MER) Spirit and Opportunity were used to acquire observations under variable illumination and viewing geometries at dedicated positions along the traverses. Such measurements were used in Hapke radiative transfer models to evaluate spectrophotometric scattering properties and microtextural variability among the rocks and soils (single scattering albedo, phase function, macroscopic roughness, and opposition effect parameters) for comparison to laboratory-based analyses [1-3]. A key part of that work involved the creation of multiple-band cubes (“Photometry QUBs”) that comprised multispectral images radiometrically calibrated to relative reflectance (IOF) and ancillary products derived from Pancam stereo models. The latter included three-dimensional maps in a rover-based coordinate system created using a modified version of the image processing pipeline used for MER operations. For a given scene, the Photometry QUBs contained the original left- and right-eye IOF images and geometrically warped right-eye data in all available filters, right and left disparity maps, Cartesian coordinate space values, range, surface normals, and incidence, emission, and phase angles. Because the derived image products typically contained some missing areas where correlations were unsuccessful, gaps were filled via interpolation to produce additional "approximated" products.

The Photometry QUBs created by [1-3] are being archived in the Planetary Data System (PDS) as PDS4 data sets with an expected released date no later than May, 2016. The Spirit data set comprises more than 250 QUB files representing 14 different locations (Sols 13-1240) along the traverse. The Opportunity data set comprises nearly 600 QUB files from 22 locations (Sols 11-1522). These data also will be accessible through the PDS Analyst’s Notebook for researchers who want to do future spectral or photometric studies with Pancam observations (http://an.rsl.wustl.edu/mer).

[1] Johnson, J.R., et al. J. Geophys. Res., 111, E02S14, doi:10.1029/2005JE002494, 2006; [2] Johnson, J.R., et al. J. Geophys. Res., 111, E12S16, 2006JE002762, 2006; [3] Johnson, J.R., et al., Icarus, Icarus, 248, 25-71, 2015.