Signature Intensity Derivative and its Application to Resident Space Object Typing

Abstract

Abstract : A key feature of resident space object (RSO) photometric signatures is change in their brightness and color with time. It has been discovered that because of the illumination angle dependency of this temporal nature, time alone is insufficient to characterize the intrinsic nature of change in signature brightness. In this paper, we present a derivation of how the first derivative of the photometric intensity as a function of phase angle is related to the normalized reflectance spectra of the materials contained in the RSO signature. It is shown for the case of the geosynchronous orbit satellite and the results of a test case in this orbit regime are presented. We discuss the implications on existing characterization algorithms and its potential for the development of new algorithms that process the photometric signatures. Finally, we discuss the insights obtained by this analysis on photometric data collection techniques.