Active Debris Removal System Development

Busek and its STTR partners are proposing two coupled Orbital Prime proposals addressing all three Tech Tracks identified in the solicitation, culminating with an active debris removal (ADR) demonstration.  Coupled proposals are required to meet the 36-month target for in-space demonstration. The key part of the ADR system is Satellite On Umbilical Line (SOUL).  SOUL is ~10kg versatile, autonomous, robotic vehicle that is deployed from a larger host space vehicle (HSV) called ORDER (Orbital Debris Remover).  SOUL and ORDER are connected by up to 50m long umbilical providing power, bidirectional telemetry and strength for towing.  SOUL has its own propulsion, proximity sensors and sufficient data processing for object (debris) recognition, relative pose estimation, way point path planning and path execution.   All of the above listed capabilities of autonomous operation have been demonstrated (on air table) under an ongoing USSF funded program to develop SOUL Inspector.  The SOUL Inspector will be converted to ADR.  The conversion is fully supported by the USSF SOUL Inspector sponsor who provided a letter of endorsement for the proposed effort. Key advantages of the SOUL technology include the avoidance of two large bodies (servicer and client S/C or a debris) making a close approach which is necessary for capturing a client with robotic arm.  Contact between two massive bodies with large momentum is likely to produce additional debris.  The SOUL offers 50m servicer to client separation, low mass and low momentum.  SOUL also offers the option of either towing or pushing the debris.  Towing avoids the need to thrust through combined center of mass. SOUL is also more likely to capture tumbling debris by better matching its motion.  Critics of the SOUL technology focus on umbilical stability in zero g environment.  However, SOUL deployment along gravity gradient is unconditionally stable.  To perform ADR, the SOUL will be equipped with a gripper that will latch onto the debris separation ring.  All space objects (CubeSats excepted) have some type of separation ring, making this approach universally applicable.  Upon mission completion the SOUL Flyer is re-stowed within the HSV/ORDER in a marsupial manner.  The mission can be repeated several times, limited by propellant on board. In this first of two parallel efforts, Busek will convert the existing SOUL Inspector into SOUL ADR by adding a robotic gripper, relocating navigation sensors and testing debris capture.  During the Phase 2 effort, the SOUL ADR system will be demonstrated in an existing RPO facility.  Testing will include autonomous recognition of the target debris and autonomous or teleoperated capture.  The debris recognition and pose estimation is performed with Artificial Intelligence (AI) algorithm developed by our STTR partner and already implemented on the SOUL Inspector.  The target debris is in the 100kg class or larger which is prioritized to prevent occurrence of Kessler syndrome.