Updates to the Oxford Space Environment Goniometer to measure visible wavelength bidirectional reflectance distribution functions in ambient conditions

Understanding how the surfaces of airless planetary bodies—such as Moon—scatter visible light enables constraints to be placed on their surface properties and top boundary layer inputs set within thermal models. Remote sensing instruments—such Diviner onboard Lunar Reconnaissance Orbiter—measure emission scattering functions across (∼0.38–0.7 µm) infrared (TIR) wavelengths (∼0.7–350 μm). To provide ground support measurements for such instruments, Oxford Space Environment Goniometer (OSEG) was built. Initially, OSEG focused measuring TIR directional emissivity regolith simulant samples in a simulated space environment, but it has recently been modified measure wavelength Bidirectional Reflectance Distribution Functions (BRDFs) ambient conditions. Laboratory-measured BRDFs can used (1) test help interpret models—such Hapke photometric model—and (2) function This paper describes modifications initial calibration taken by Visible with 532 nm laser, details this setup bodies.