Solar calibration targets characterization after on-orbit environmental impact

Bidirectional Reflectance Distribution Function (BRDF) characterize the materials surface as a function of wavelength, illumination and scattering geometry. BRDF determines the amount and angular distribution of optical scatter from a surface. It is eminent to remote sensing, material science and engineering, computer graphics and other applications. We were granted opportunity to participate in Materials International Space Station Experiment (MISSE) to evaluate recently created solar diffusers optical properties after space flight including their degradation due to exposure to the space environment as ultraviolet irradiation, atomic oxygen fluence, temperature and contamination. Several types of newly developed solar diffusers participated in the experiment. The solar diffusers have been exposed to the space environment for 2440 hours. The Directional Hemispherical Reflectance (DHR) and BRDF of the diffusers were measured and compared to those of reference diffusers not exposed to on-orbit space environment. Special attention was paid to the on-orbit degradation of the solar diffusers during expected on-orbit lifetime of the instrument. The solar diffusers were characterized at NASA’s Goddard Space Flight Center (GSFC) Radiometric Calibration Facility using the Facility’s Optical Scatterometer. The measurements are traceable to NIST Robotic Optical Scattering Instrument (ROSI).