Abstract: The development process of Geostationary Earth Orbit robotic programs sponsored by Defense Advanced Research Program Agency (DARPA) is summarized. Then, the key technologies including space robotic arm design, detection, recognition and relative navigation of non-cooperative target, safety approaching and docking, coordinated control for robotic arm and spacecraft bus, compliant control for cooperatively delicate operation of multiple arms, space teleoperation, and ground simulation and test, are analyzed. Several enlightenments are presented, and some suggestions are brought forward in the end.