Attitude Dynamics Simulation of MLI Space Debris Objects in Geosynchronous Earth Orbits

Abstract

The orbital and attitude dynamics of uncontrolled Earth orbiting objects are perturbed by a variety of sources. In research, emphasis has been put on active space vehicles. Active satellites typically have a compact shape, and hence, a low area-to-mass ratio (AMR), and are in most cases actively or passively attitude stabilized. This enables one to treat the orbit and attitude propagation as decoupled problems, and in many cases the attitude dynamics can be neglected completely. The situation is dierent for space debris objects which are in an uncontrolled attitude state. Furthermore, the assumption that a steadystate attitude motion can be averaged over data reduction intervals may no longer be valid. Additionally, a subset of the debris objects have signicantly high AMR values, resulting in highly perturbed orbits, e.g. by solar radiation pressure, even if a stable AMR value is assumed. Note, this assumption implies a steady-state attitude such that the average cross-sectional area exposed to the sun is close to constant. Time-varying solar radiation pressure accelerations due to attitude variations will result in un-modeled errors in the state propagation. The current paper investigates the evolution of the coupled attitude and orbit motion in simulating the object properties of pieces of multilayer insulation (MLI) materials Kapton R and PET R . Double and single aluminum coating is regarded as well as the tendency of the materials to curl up. The objects are simulated to be in a near geosynchronous orbit. It is assumed the objects are rigid bodies and are in non-controlled attitude states starting with zero attitude motion. The integrated eects of the Earth gravitational eld and solar radiation pressure on the attitude motion are investigated. The light curves, that is, the brightness variations over time as observed from a ground based optical sensor are generated.