Photograph of Astronaut Bruce McCandless II during the First Field Tryout of the Manned Maneuvering Unit

Original caption: Astronaut Bruce McCandless II, one of two 41-B mission specialists participating in an extravehicular activity, approaches his maximum distance from the Earth-orbiting space shuttle Challenger. McCandless and his MMU have moved further away from the Challenger en route to a point some 90 meters away. McCandless is in the midst of the first field tryout of the nitrogen-propelled, hand-controlled device called the manned maneuvering unit which allows greater mobility than the use of restrictive tethers.
Photographs Relating to Space Exploration