SPHERES (Synchronized Position Hold, Engage, Reorient Experimental Satellites) are experimental robots made at MIT for the purpose of testing robot locomotion in space. As you can see in the video above, they are capable of maneuvering pretty well. They seem to hold formation fairly tightly. They are using compressed CO2, through 12 different thrusters for positioning. They should be capable of autonomously navigating around each other as well as docking to one another.