Development of a Nanosatellite De-Orbiting System by Reliability Based Design Optimization
CHALLENGE - This paper presents design approaches to develop a reliable and efficient de-orbiting system for the 3USAT nanosatellite to provide a beneficial orbital decay process at the end of a mission. This paper extends previous studies by comparing deterministic and probabilistic optimization results while still employing MCS, FORM and SORM techniques for reliability.
SOLUTION - For the multi-objective design, the objectives are chosen to maximize the aerodynamic drag force through the maximization of the Kapton surface area while minimizing the de-orbiting system mass. The 3 design constraints are: the height of the solar panel hole which determines the area that the folded Kapton material occupies, the deployment angle which determines the orientation of the Kapton material with respect to the satellite structure after deployment, and the force required to start deployment. Optimization variables are the length and number of layers of the Kapton structure. On the other hand, the uncertainties, which can arise from manufactoring tolerances and unmodelled or uncertain atmospheric conditions could significantly affect the system reliability.The reliability based optimum design yields the best solution since it improves both system reliability and performance requirements.
BENEFITS - The optimization was performed by implementing an in-house MATLAB code to compute the criteria for the deployable system and the optimization software, modeFRONTIER using algorithm MOGA-II. Although large differences in results were not seen between reliable optimums, the design produced by SORM based optimization had a shorter decay time (14.0 years) than the FORM technique and considered to be the final design.