Spacecraft, Free-Falling Satellites Perform ‘Delicate Dance’

While active satellite and spacecraft rely on thrusters to control movement, retired  space assets tumble at high speeds through their orbits.

This causes a problem when a spacecraft needs to rendezvous with a satellite in free fall. The Defense Advanced Research Projects Agency is working with researchers around the world — including high schoolers — to solve the problem of synchronizing the movements of tumbling objects in space.

Scientists began their research as part of a competition to control bowling ball-sized SPHERES — synchronized position, hold, engage and reorient experimental satellites — aboard the International Space Station. Teams used algorithms in exercises during which the spheres simulated an active spacecraft approaching an object tumbling through space. At least one of the teams was successful in every scenario presented.

To bring the research to scale, DARPA will transition findings to another program aimed at developing technologies to reuse components from retired communications satellites in geosynchronous orbit. This will require a spacecraft to maneuver itself into position and synchronize with a tumbling object in such a way that tools can be used to remove or attach parts.

“Our efforts can help to reduce the risks and costs of future complex satellite-to-satellite interactions in space to lower the barrier of entry for future space operations and missions,” DARPA Program Manager Dave Barnhart said.

The agency will hold more competitions to refine algorithms for the synchronized tumbling officials described as a “delicate dance.” The latest contest helped identify ways to optimize fuel use and time to mirror an object’s random tumble in space, as well as safely approaching and docking with it, Barnhart said.

Photo Credit: DARPA

Topics: Science and Engineering Technology, DARPA, Space