Jason Forshaw, Astroscale; Mike Lindsay, Astroscale; Charity Weeden, Astroscale; John Auburn, Astroscale; Chris Blackerby, Astroscale
Keywords: ADR, debris, removal, OOS, servicing, SSA, tumbling, characterization
Abstract:
Comprehensive Space Situational Awareness (SSA) data allows users to accurately interpret and characterize the activity of satellites, improving operational safety and reducing the risk of collisions by increasing ability to recognize abnormal or off-nominal behaviour. In the years since its origin, there have been increasing use cases for SSA, such as asset investment protection, insurance claims, and safety of flight. Now with the advent of new Active Debris Removal (ADR) and In-orbit Services (IOS) missions, SSA becomes an important part of operational services.
Astroscale is one of the few companies in the world proposing to aid in the removal of orbital debris through the provision of two services: end-of-life (EOL) targeting the LEO constellations, and ADR targeting existing larger space debris. Astroscale is working on a variety of project and future missions in this arena. These include the ELSA-d mission (the world’s first commercial demonstration of ADR, launching in 2020), commercial developments under the ESA Sunrise Programme with OneWeb to mature technology for future end-of-life missions, and the institutional ADRAS-J mission (JAXA’s first mission ADR to observe debris, in light of future removal).
As we grow our business, develop our capabilities, and become closer to fully operational services, Astroscale is developing a clearer understanding of SSA needs for its future ADR missions. This paper aims to address those specialised needs, understanding the key technical drivers. In a classical ADR mission, there is a servicer (the vehicle doing the removal) and client (the asset in space being removed) – generally the client is defunct and thus its position can only be known through use of SSA services.
We break down our SSA needs into 5 categories, which will be explored in depth in the paper. Firstly, SSA can provide pre-launch assessment (1) – important data can be provided by SSA even before a servicer is launched, such as client position and, in some cases, client attitude and tumbling rate. SSA is mandatory for future search and approach manoeuvres (2). This is because the client is defunct (for example, GPS can’t be used) and thus the only positioning data comes from SSA sources. As the servicer finds and rendezvous with the client, SSA data is needed before the servicer performs a handover to relative navigation at closer distances. This section will explore aspects of SSA data needs such as data accuracy, quality, timeliness and availability, with respect to the RPO (rendezvous and proximity operations) sequences on our missions. SSA services can provide some form of failure analysis capability (3), to analyse the conditions surrounding the failure of the client. Understanding such information before rendezvous, could be very valuable to the ADR service provider. Collision analysis and CAM alerts (4) are a core stable of conventional SSA provision and are also needed in ADR missions. Finally, regarding safety and security (5), SSA can provide independent monitoring for ensuring transparency for any regulatory and potential insurance compliance. In particular, tracking of the servicer during the course of the mission can provide confidence that no malicious behaviour is being undertaken.
In addition to the SSA needs discussed above, the paper will provide an overview of each core phase of the concept of operations (CONOPS) and how SSA is needed in each phase of the mission.
This paper overall provides a unique customer-side insight into SSAs needs for ADR. As Astroscale are one of the first users of SSA for this specific application, we are a core player driving the way SSA provision evolves in future to support these missions.
Date of Conference: September 15-18, 2020
Track: Orbital Debris