Speaker
Description
The increasingly crowded space environment and the growing risk of collisions with space debris, active and inactive satellites necessitate a shift from traditional ground-based orbit maintenance and collision avoidance (CA) strategies to autonomous onboard solutions. This paper expands upon the work presented by GMV at the 9th European Conference on Space “A Modular And Scalable Collision Avoidance System For Enhanced Satellite Autonomy, 2025” focusing on developments within the OCAD project.
OCAD (On-board Autonomous Collision Avoidance Detection Testbed) aims to develop a testbed to validate the design of a standalone satellite payload capable of performing autonomous on-board collision avoidance, including capability as inter-satellite communication and on-board secondary detection.
The self-contained payload (of mass < 10kg) is designed to provide real-time orbit determination and propagation, conjunction detection, risk assessment and autonomous collision-avoidance manoeuvre computation to a host-satellites, using standard spacecraft interfaces.
Its primary function is to detect potential conjunction with other spacecraft operating in its vicinity and to continuously forecast its own short-term orbital position and velocity. These forecasts are also shared with nearby spacecraft equipped with an OCAD payload while at the same time, it receives orbit-prediction data from neighbouring spacecraft which is added to an on-board minicatalogue of neighbourhood objects uploaded from ground. This functionality not only allows to provide more up-to-date and accurate spacecraft states for the CA decision chain but also can enable cooperative CA strategies.
For any potential collision risks, a safe and efficient CA manoeuvre is computed with consideration given to safe corridors and potential downstream conjunctions. Validated manoeuvres are provided to the host platform AOCS via thrust vectors and a decision flag.
To support its autonomous decision-making, OCAD will perform onboard orbit determination and produce short-term forecasts of its orbital position and velocity and corresponding covariance, providing improved accuracy compared to longer-horizon estimates generated by ground-based surveillance systems. The payload is designed to operate in both LEO and GEO environments through the selection of robust methods for both short-term and long-term encounters.
On-board autonomous secondary orbit determination of uncatalogued debris objects or the refinement of catalogued object covariance using an optical payload is also a baseline capability of the payload. Any identified objects could be added to the minicatalogue providing enhanced situational awareness further decreasing the risk of collisions. The benefits of such a solution are under study and will be an outcome of the testbed development.
The OCAD system enhances a spacecraft’s ability to take timely and effective action to avoid collisions, directly contributing to the implementation of ESA’s Space Debris Mitigation Policy by enabling autonomous collision-avoidance capabilities that reduce the risk of in-orbit fragmentation events. Overall, OCAD strengthens compliance with ESA guidelines aimed at preventing the creation of new debris and ensuring long-term orbital safety. This paper will present the OCAD testbed design which will be used to model the proposed payload and assess the autonomous capabilities of the stand-alone system.