SPHERES Zero Robotics Test Session

ISS038-E-014012 (9 Dec. 2013) --- In the International Space Station's Kibo laboratory, NASA astronauts Rick Mastracchio (left) and Michael Hopkins, both Expedition 38 flight engineers, conduct a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES.