Space Object Radiometric Modeling for Hardbody Optical Signature Database Generation

摘要

Recent advances in spacecraft health monitoring have resulted in successful applications of photometry and light curve analysis to quantify measurable changes to the spacecraft by passive means. Subtle changes in degradation of spacecraft material properties, reorientation of central body attitude, and slight misalignment of major signature producing components (extended solar panels) are often detected under nonoptimized viewing conditions. It is beneficial to the observer/analyst to understand the fundamental optical signature variability associated with these detection and identification processes. This paper captures the fundamental observable variations of representative convex surfaces that may exist in the surround for which the subtle change processes need to be detected. The key surface parameters include shape, orientation, altitude, surface - sensor - light source scenario, and material reflection characteristics. Specifically, this paper summarizes radiant intensity patterns as a function of prioritized key parameters as generated from moderate to high-fidelity simulations. The intent is to provide the analyst with an information-based capability to select the observation - sensing scenario that has an increased likelihood of successfully monitoring changes to the spacecraft. The focus of the paper is to present a graphical database summary of typical meter-size convex surfaces that include a right circular cylinder, a right circular conical frustum, a right circular cone, and a thin circular disk. These objects are modeled in their major in- plane and out-of-plane orientations with respect to the sun and the earth, while situated at a low earth orbit (LEO) and a geostationary earth orbit (GEO) altitude location. Results are presented for broad visible spectral band observations as the sensor performs a complete 'walk around' of the objects in the.