Space object material determination from polarized light curves

Surface material identification of resident space objects is demonstrated using polarized monochromatic light curves. The specular reflection of unpolarized light off a flat surface creates a reflection that is partially polarized. This polarization depends on the index of refraction and the extinction coefficient of the reflecting material. Thus, the degree of polarization contains information about the surface material that is not contained in the unpolarized light curve. A polarized bidirectional reflectance distribution function is developed to generate polarized light curves. Surface material observability is analyzed. Multiple-model adaptive estimation is used to identify the surface material from a bank of candidate materials when specular reflection occurs. Results indicate that the polarized light curves can accurately determine material properties os a resident space object.