Nasa Challenge for High School Teams
 

WASHINGTON -- NASA is challenging high school teams to design software to program small satellites aboard the International Space Station. The competition centers on the Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES.

SPHERES are bowling ball-sized spherical satellites used to test maneuvers for spacecraft performing autonomous rendezvous and docking. Three of these satellites fly inside the station's cabin. Each is self-contained with power, propulsion, computing and navigation equipment.

More info here