INTEGRATED ONBOARD AUTONOMOUS COLLISION AVOIDANCE

OB-ASTRA (On-Board Autonomous Space Traffic Risk Avoidance), developed under ESA ARTES 4.0 AT Programme, is a device supporting space debris miti- gation. OB-ASTRA enables fully autonomous collision avoidance while provid- ing accurate attitude and orbit determination using standard spacecraft sensors, namely star trackers and GNSS receivers. As conjunction events approach, OB- ASTRA autonomously detects candidate events and refines avoidance decisions through onboard tracking. For efficient constellation operations, the device inte- grates a low power intersatellite link to support communication between OB- ASTRA nodes. The system interfaces with existing operational infrastructures via a ground com- panion application and a web server, enabling a scalable space traffic management network. The host spacecraft operator acts primarily as a supervisor, intervening only in case of anomalies or when manual control is explicitly required. Simulations indicate that OB-ASTRA can reduce propellant consumption due to false alarms by typically about 6% compared to a standard ground-based approach in non-cooperative scenarios, while substantially off-loading routine conjunction assessment tasks from ground. In cooperative scenarios, GNSS-grade ephemeri- des sharing further increases the benefit of late maneuver execution, yielding sig- nificantly larger propellant savings. OB-ASTRA is currently in the design phase; an engineering model is expected in 2026, with TRL 5 validation targeted for year-end 2026.