The U.S. Defense Advanced Research Projects Agency (DARPA) will launch the Zero Robotics Autonomous Space Capture Challenge on March 28, a contest that asks participants to develop unique algorithms to control small satellites on-board the International Space Station (ISS). The algorithm must enable a satellite to capture a space object that is tumbling, spinning, or moving in the opposite direction. Participants can collaborate via the Zero Robotics Web site to create algorithms that will be programmed into Synchronized Position, Hold, Engage, and Reorient Experimental Satellites (SPHERES). For the challenge, an object, simulating a payload on-orbit delivery system, will be set in motion inside the ISS under varying conditions. The algorithm will need to direct the satellite to approach the moving object and orient itself to contact with the object via Velcro on the SPHERES satellites. In addition, DARPA's Phoenix program aims to develop technologies that could help a new spacecraft harvest and reuse valuable components from nonworking satellites in geosynchronous orbit. "If a programming team can solve this challenge of autonomous space object capture, it could not only benefit the Phoenix program directly but potentially any space-servicing system in the future," says DARPA's Dave Barnhart.