Risks of Secondary Space Debris Generation from Net Capturing in Active Space Debris Removal Missions

Abstract

Mitigation strategies which eliminate existing space debris, such as with Active Space Debris Removal (ASDR) missions, are now more important than ever regarding the ever-growing space debris population problem. One of the considered ASDR approaches uses a net as a capturing strategy. The benefits of such strategy are to allow for a large capturing distance, high compatibility for different space debris sizes and reduced accuracy requirements.

A key requirement of any ASDR missions is that during capture, no new space debris is to be generated during the process. However, when simulating net capturing in the literature, the potential to break of vulnerable structures, like antennas or solar panels is often neglected. Such elements may show an enhanced risk of failure, especially if these are already damaged, potentially contributing to even more space debris.

A discrete Multi-Spring-Damper net model was used to simulate the 20 m/s-frontal impact of a 30 m x 30 m net onto an ESA Envisat mock-up. The Envisat was modelled as a two rigid-body system with a Single-Degree-of-Freedom hinge connection. A sequential modelling strategy was implemented, which de-coupled all the necessary dynamic and structural models. More than two large sub-structures (the Ka-band antenna dish and solar array) were found to have a high likelihood of breaking, leading to the recommendation of several design mitigation strategies using two types of sensitivity analysis. With secondary space debris being generated, net capturing is found to be riskier than originally assumed throughout the literature.