There is an ever-growing need for orbital debris mitigation as the number of spacecraft launched into Low Earth Orbit continues to significantly increase. While relatively simple drag sail devices, such as Nanosail-D2 and Surrey’s InflateSail have been shown to be effective in reducing deorbit times to within an acceptable range, these sails have not been capable of orbital maneuvering to allow for controlled, targeted re-entry. Being able to actively change orbital inclination and/or throttle drag area to control re-entry location could be a game-changing capability. In response to NASA’s desire for such a capability, Roccor proposes to develop the Sail Trimming ActuatoR for Targeted Reentry (STARTR) system. This simple, small and lightweight system can be used to guide the spacecraft to a known reentry point. The key enabling technology for STARTR is a gimballed boom that controls the relationship between a planar drag sail’s center-of-pressure (CP) and center-of-gravity (CG) to induce attitude control torques large enough for orbit changing maneuvers. Furthermore, Roccor envisions a retractable sail membrane that can be used to throttle the effective drag area up or down to further fine-tune reentry time and location. The system is designed to easily scale for a given spacecraft mass and size. The proposed Phase I effort will involve the conceptual development of the STARTR system, including system modeling and analysis for stability (aero- and gravity gradient), orbital trajectory manipulation and drag throttling.
The proposed STARTR system could be applied to spacecraft end-of-life deorbiting, especially in situations where there is a concern over on-orbit collisions with other objects, or human safety on the ground, or if there is a desire for object retrieval in a known location after reentry. Similarly, the STARTR device could be used for targeted Entry, Descent and Landing (EDL) operations for planetary science missions. And finally, the STARTR technology could also be utilized to steer a solar sail.
With regulatory bodies such as the FCC becoming more stringent about spacecraft deorbit requirements, the STARTR technology is envisioned to be an excellent candidate drag sail technology for use on commercial CubeSats or SmallSats.