WRANGLER: Capture and De-Spin of Asteroids and Space Debris

Closeout Summary: The Phase I WRANGLER effort has demonstrated the feasibility and value of using a small tethered nanosatellite to accomplish capture and de-spin of space objects for future NASA and commercial efforts to acquire space resources from asteroids and actively remediate the space debris population. Current baseline architectures for capturing large space objects such as Near Earth Asteroids or spent rocket bodies rely upon a single high-value spacecraft to capture and reposition the target object as well as the use of thrusters to de-spin the object to allow maneuvering. Through detailed physics-based simulations we have demonstrated that tethered nanosatellites deployed from even the most massive fast rotators are effective at dramatically reducing the target's body rates and can be successfully controlled using simple control laws and high-TRL tether deployment hardware. We have developed two WRANGLER system concept designs capable of serving a variety of Asteroid Redirect Mission (ARM) and Active Debris Removal (ADR) CONOPS. The first is a small 2U picosatellite used simply as a means of de-spinning the target and the second is a larger free-flying nanosatellite used to both capture and de-spin the target object. Comparison of these concept designs to conventional propellant-based approaches has demonstrated the significant mass savings afforded by the WRANGLER concept. Furthermore, fractionation of the mission architectures by using a tethered nanosat for capture and de-spin can signficantly reduce the risks and requirements imposed on large primary mission spacecraft. The technologies required to provide the benefits of the WRANGLER system are all hardware of mid- to high-TRL. TUI's evaluation of the technology readiness of the concept indicates that a WRANGLER system that has the potential to provide order-ofmagnitude performance improvements can be designed and integrated with minimal effort and modest investment. While the remaining risks of the WRANGLER system are non-trivial, they are well understood and have clear and proven mitigation strategies that can be implemented with the proper engineering effort. WRANGLER provides significant benefits to ARM, ADR and future commercial space resource development efforts by replacing hundreds or thousands of kilograms of propellant with a small, low-mass, low-cost system capable of enabling space systems to safely gain control of large space objects.