1937-

American astronaut who was the first individual to spacewalk untethered. McCandless graduated from the U.S. Naval Academy and Stanford University, specializing in electrical engineering. McCandless contributed to the development of the manned maneuvering unit, testing it during a 1984 shuttle flight. He demonstrated how extravehicular activity free of connecting lines could be useful in repairing satellites. In 1990 McCandless and crewmates deployed the Hubble Space Telescope. After that mission he applied his knowledge to the international space station's construction.