Docking device for spacecraft gets a redesign

Aug. 19, 2004

As the U.S. becomes more and more dependent on satellites for communications, reconnaissance and defense, and the cost of sending humans to service them remains high, the Air Force and Darpa are looking for ways to autonomously rendezvous, dock, and repair space assets.

As part of this effort, engineers at Michigan Aerospace Corp., Ann Arbor (www.michiganaerospace.), redesigned a docking system specifically for refueling and servicing microsatellites i.e., those weighing under 1,000 lb. The goal was to make it smaller, lighter, and less complicated.

The new Autonomous Microsatellite Docking System (AMDS) uses a cable with a latching end effector that extends into a conical alignment socket and an inert receptacle. This lets docking vehicles rendezvous with unpowered satellites. The cable is withdrawn, pulling the spring-loaded, conical, male docking probe into the female target cone and aligning the two spacecraft using the cone-shaped mating surfaces and three alignment posts mounted around the probe. An earlier system used more-complicated latching posts. Once aligned, the cable withdraws again, pulling the posts completely into their mating sockets and restraining motion between the two spacecraft in all six degrees of freedom. When the mission is complete, the cable latch releases and the springloaded probe gives the docking vehicle a controlled push away from the satellite.