REMORA CubeSat for large debris rendezvous, attachment, tracking, and collision avoidance

This paper presents the feasibility study of the REMORA CubeSat mission concept with an integrated miniature robotic payload to prevent large debris collisions. While orbital debris poses a threat to spacecraft, a collision between the largest space debris objects is of significant concern. The DARPA Catcher's Mitt study compiled a list of the highest priority large debris objects. By annually removing 5-10 of these high priority objects, it may be possible to stabilize the medium sized debris population. Instead of deorbiting objects, REMORA would use COTS CubeSat components and secondary payload launches as a cost-effective solution for mitigating large debris collisions. The REMORA CubeSat could rendezvous with a piece of debris and use the robotic manipulator to anchor itself to the target object. Once anchored, the CubeSat could track the debris and, if needed, alter the debris object's trajectory to prevent a collision. Aspects discussed include the mission and robotic payload baseline designs. Many of the highest priority objects identified in the DARPA Catcher's Mitt study are located in the 71°-75° inclination range and in sun-synchronous orbit. An initial mission design concept targets sun-synchronous objects due to the large number of launch opportunities to this orbit. The mission was simulated with a combination of MATLAB, GMAT, and STK. A CubeSat robotic payload was designed to provide a decreased chance of collision between the CubeSat and debris object during attachment, augment the ACS during approach, and provide the ability to orient the thrust vector through the center of mass while pushing. This robotic payload includes a computing element, cameras, miniature robotic arm, and end-effector. An initial miniature arm prototype was designed and built to demonstrate feasibility and inform future designs. An end-effector trade study was performed to explore different end-effectors that could be used to for attaching to the common graspable features on large debris objects. Grasping methods, including mechanical prehension, gecko grippers, electrostatic grippers, and magnetic grippers, were investigated.