(9 Feb. 1984) --- Astronaut Robert L. Stewart appears to glide a few meters above the Earth-orbiting Space Shuttle Challenger's cargo bay during the second of two extravehicular activity (EVA) session on the Challenger's fourth flight in space. Astronauts

(9 Feb. 1984) --- Astronaut Robert L. Stewart appears to glide a few meters above the Earth-orbiting Space Shuttle Challenger's cargo bay during the second of two extravehicular activity (EVA) session on the Challenger's fourth flight in space. Astronauts Stewart and Bruce McCandless II, two of NASA's three mission specialists on flight STS-41B, earlier made another EVA, testing another manned maneuvering unit (MMU). (Photo by: HUM Images/Universal Images Group via Getty Images)