NASA's planned Solar Probe mission is designed to gather information about the near sun environment at a distance of approximately ~10 solar radii.  The conditions near the sun are quite harsh, which necessitate the application of engineered material systems, which will fulfill the role of a thermal barrier to protect the sensitive instruments on board the spacecraft.  The purpose of this project is to characterize the optical properties of the materials under consideration in conditions that are similar to those found near the sun.  Under this program test samples of the prospective materials will be subjected to high temperature vacuum conditions and lasers at discrete wavelengths will be used to measure the optical reflectivity to determine the bidirectional reflectance distribution function (BRDF) of the materials.  Candidate materials being investigated include alumina, boron nitride and composites of these ceramics.