Toby Harris, Astroscale UK; Jason Forshaw, Astroscale UK; Mike Lindsay, Astroscale Japan; George Brydon, Astroscale UK; Alek Lidtke, Astroscale Japan; Neil Yarr, Astroscale UK
Keywords: In-situ SSA, RPO, ADR, ELSA-d, operations, rendezvous proximity operations
Abstract:
T. Harris1*, J. Forshaw1†, A. Puppa1, M. Lindsay2
* speaker † corresponding author
1 ASUK, 2 ASHD
Astroscale’s ELSA-d mission, the world’s first commercial demonstration of an end-of-life (EOL) capability is be used to demonstrate the core technologies necessary for debris docking and removal. The uniqueness of the mission objectives and its operations provide an exclusive opportunity to explore both the Space Situational Awareness (SSA) demands on future Rendezvous and Proximity Operation (RPO) missions, as well as potential uses of the demonstration technologies to support SSA services.
The ELSA-d mission consists of two spacecraft, a servicer and a client, stacked together during launch and orbit insertion. The servicer is equipped with proximity rendezvous technologies and a magnetic docking mechanism, while the client has a ferromagnetic plate which enables the docking. The servicer will repeatedly release and dock with the client in a series of technical demonstrations proving the capability to find and dock with debris. Demonstrations include client search, client inspection, client rendezvous, and both non-tumbling and tumbling docking.
Because of the controlled nature of this specific mission – Astroscale has direct command and control of both spacecraft – ground-truth instrumented data, including accurate time-dependent state-vectors and spacecraft dynamics, are readily available. This enables evaluation of the use of SSA services during the key phases of the mission. This paper seeks to assess SSA requirements including orbit propagation and determination of both spacecraft, attitude analysis (state and evolution rate), approach analysis and collision avoidance. By evaluating these needs during and post-mission, it is hoped that a better understanding of what services are either essential or desirable for future RPO missions, whether they be Active Debris Removal (ADR), EOL, In-orbit Inspection or Life Extension (LEX).
As well as assessing SSA needs, ELSA-d also offers the prospect of considering how bespoke RPO technologies onboard the spacecraft could be used to support other SSA mission objectives. The ELSA-d spacecraft has several sensors designed for close-proximity analysis and inspection which could potentially be used to explore In-situ SSA application. This includes, for example, small-debris characterisation in LEO and large object identification in GEO. This paper seeks to explore some of these activities and consider the results from these on-orbit experiments, as well as draw some preliminary conclusions on the efficacy of these types of systems.
Date of Conference: September 14-17, 2021
Track: Conjunction/RPO