An Attitude-Independent Parachute for De-orbiting Inoperative Satellites

Space debris is a growing concern in low Earth orbit (LEO), with the potential to pose a threat to all active satellites and spacecraft. A key way to mitigate this problem is to ensure objects in LEO are actively removed from orbit at the end of their useful lifetimes, as deorbiting can take upwards of 100 years naturally. With large satellite constellations increasing each year, it has been simulated that a post-mission disposal reliability of 99.9% should be aimed at, for reducing growth. In the years 2000-2016, 35.2% of small satellites failed during their operational lifetimes, necessitating the use of external devices for deorbiting. Current drag sail simulations and experiments fail to demonstrate passive stability, therefore requiring an active attitude control system for years post End-Of-Life to swiftly deorbit. Thrusters and electrodynamic tethers also require functional subsystems, and therefore cannot reach the required reliability, meaning a novel device must be designed. Various shapes and materials for a 3D, attitude-independent drag device are explored as part of this study, simulated through CNES STELA and ESA DRAMA, to find the optimal configuration. The device aims to enable deorbiting for out-of-control satellites, while staying mass efficient. Based on the analysis, an open tetrahedron was found to be the optimal solution, currently deploying with CFRP or metal booms. The device requires further testing to validate the reliability and feasibility for practical implementation but offers a promising solution for reducing the collisional debris growth.