Thermal infrared radiation calculation of orbital objects with micro-motions

Effect of micro-motion dynamics on infrared (IR) radiation signatures for orbital objects is studied in this work, by considering the micro-motion modes and physical principles based heat transfer. Micro-motion modes of an object on orbit such as spin stabilization, three-axis stabilization or roll motion are modeled using Rodrigues formulation. Heat transfer equations, including three-dimensional (3-D) heat conduction, radiation on outer surface including thermal dissipation as well as heating from the sun and earth, and thermal radiation on innermost surface, are formulated and solved using numerical techniques to obtain the time-evolving temperature field on the object. IR signatures in 8~16µm bands are calculated by integrating the self-emitted and surface-reflected components, with different surface emissivity being considered. Numerical results of the micro-motion effect on IR signatures for a cylindrical object on orbit are presented with in-depth phenomenological analysis.