Satellite formation flight and realignment maneuver demonstration aboard the International Space Station

Abstract

The Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES), developed by the MIT Space Systems Laboratory, enable the maturation of control, estimation, and autonomy algorithms for distributed satellite systems, including the relative control of spacecraft required for satellite formation flight. Three free-flyer microsatellites are currently on board the International Space Station (ISS). By operating under crew supervision and by using replenishable consumables, SPHERES creates a risk-tolerant environment where new high-risk yet high-payoff algorithms can be demonstrated in a microgravity environment. Through multiple test sessions aboard the ISS, the SPHERES team has incrementally demonstrated the ability to perform formation flight maneuvers with two and three satellite formations.The test sessions aboard the Space Station include evaluation of coordinated maneuvers which will be applicable to interferometric spacecraft formation missions. The satellites are deployed as a formation and required to rotate around a common center about a given axis, mimicking an interferometer. Various trajectories are then implemented to point the synthetic aperture in a different orientation by changing the common axis of revolution. Observation-time optimizing synchronization strategies and fuel balancing/fuel optimizing trajectories are discussed, compared and evaluated according to resulting mission duration and potential scientific output.

Architecture for in-space robotic assembly of a modular space telescope

“…Guidance and control algorithms needed for autonomous and precise spacecraft formation flight have been demonstrated, including ground-based demonstrations in JPL's Formation Control Testbed, 44,45 through applications such as starshade missions. 46 On-orbit demonstrations of autonomous formation flight have also been successfully achieved with the Prisma mission, 47 the TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) mission, 48 with CubeSats, 49 within the confines of the ISS on the Synchronized Position Hold Engage Re-orient Experimental Satellites (SPHERES) testbed, 50 and achieving science with the upcoming external coronagraph Proba-3 mission. 51 Depending on the telescope size and the orbital environment, formation flying may be required or may be infeasible.…”

Formation control and reconfiguration through synthetic imaging formation flying testbed (SIFFT)

“…For example, the same relative search strategy was used in another test during the same ISS session and the angle was approximately 85˚ in the end of the test. More of the ISS test results are presented and discussed in a separate paper [7]. Although the test suffered from the multi-path problem of the U/S signal, it successfully demonstrated the adequacy of the present search strategy on hardware in 3D space.…”