Speaker
Description
The PRELUDE mission, developed by ClearSpace in partnership with ESA’s Space Safety Programme, is an in-orbit rendezvous and proximity operations (RPO) demonstrator which embodies the practical implementation of space safety principles.. The mission addresses a central challenge for future in-orbit servicing (IOS) and active debris removal (ADR): how to safely design, operate, and conclude missions requiring close approach in congested orbital environments.
PRELUDE consists of two identical cubesats executing a stepwise RPO campaign in Low Earth Orbit, from relative separation of tens of kilometres down to a few metres. Safety is embedded by design with a ConOps which implements an incremental approach performing commissioning of functions before use, and makes use of passively safe relative orbits wherever possible, ensuring collision-free behaviour even in the event of anomaly
During proximity operations, PRELUDE implements layered safety mechanisms combining onboard autonomy and ground oversight. These include autonomous collision avoidance manoeuvres (CAM), RPO-specific fault detection, isolation and recovery (FDIR), safety corridors, and cooperative safety functions implemented on both spacecraft. The mission demonstrates how the responsibility for safety can be effectively shared between flight software, payload systems, and operations teams during critical phases.
Operating in LEO—where environmental disturbances and conjunction density are most demanding—provides a robust validation of safety-critical GNC sensors and algorithms, including vision-based relative navigation and six-degree-of-freedom control. PRELUDE extends space safety through the full lifecycle, including passivation and end-of-life disposal therefore offering a complete reference for Space Safety mission implementation in future close-proximity missions.