Side close-up view of crewman in high-fidelity Extravehicular Mobility Unit (EMU) / Manned Maneuvering Unit (MMU) mockup.

Astronaut Bruce McCandless during an underwater test of the Manned Maneuvering Unit (MMU) Flight Support Station (FSS) donning and doffing in the Bldg 29 Weightless Environment Training Facility (WETF). View is of McCandless wearing the extravehicular mobility unit (EMU), stepping into the MMU.

S84-27021 (7 Feb 1984) --- Astronaut Bruce McCandless II, 41B mission specialist tests a "cherry-picker" type device during February 7 historical Extravehicular Activity (EVA). The EVA, in which Astronauts McCandless and Robert L. Stewart, two of three STS-41B mission specialists, participated, marked two firsts--initial use of both the Mobile Foot Restraint (MFR) attached to the Remote Manipulator System (RMS) arm here, and the Manned Maneuvering Unit (MMU) backpack (not seen in this frame). The Challenger was flying with its aft end aimed toward the Earth. This photograph clearly shows where the MFR connects to the end effector of the Canadian-built RMS arm. The two spacewalkers were monitored and photographed by their fellow crewmembers, astronauts Vance D. Brand, commander; Robert L. Gibson, pilot; and Ronald E. McNair, mission specialist. The three remained in the cabin for another EVA session two days later. Photo Credit: NASA

41C-22-885 (8 April 1984) --- The 35mm camera was used to photograph this scene of Astronaut George D. Nelson, STS-41C mission specialist, as he uses the manned maneuvering unit (MMU) to make an excursion to the plagued Solar Maximum, Mission Satellite (SMMS)._Astronaut James D. van Hoften remained in the Challenger's cargo bay during the April 8 extravehicular activity (EVA).

S82-27594 (25 Feb 1982) --- Astronaut Bruce McCandless II models NASA?s extravehicular mobility unit (EMU) spacesuit for Shuttle and the backpack unit (called a manned maneuvering unit) that will give future STS crewmembers extended mobility in space. A forerunner version of the MMU?called an astronaut maneuvering unit?was tested internally on Skylab. The MMU will allow astronauts for the first time in history to move about in the vicinity of their spacecraft without being tethered to the ship. McCandless was giving a demonstration of the EMU/MMU in JSC?s laboratory support facility.

S84-27031 (7 Feb 1984) --- Astronaut Bruce McCandless II, 41-B mission specialist, reaches a maximum distance from the Challenger before reversing direction his manned maneuvering unit (MMU) and returning to the Challenger. A fellow crewmember inside the vehicle's cabin took this photograph with a 70mm camera. The untethered EVA marked the first such experience for astronauts.

S84-27232 (& Feb 1984) --- Astronaut Bruce McCandless II, 41-B mission specialist, uses his hands to control his movement above the Earth - and just few meters away from the Challenger - during the first-ever extravehicular activity (EVA) which didn?t use restrictive tethers and umbilical?s. Fellow crewmembers aboard the Challenger used a 70mm camera to expose this frame through windows on the flight deck. McCandless was joined by Robert L. Stewart, one of two other mission specialists for this flight, on two sessions of EVA.

S80-36889 (24 July 1980) --- Astronaut Bruce McCandless II uses a simulator at Martin Marietta?s space center near Denver to develop flight techniques for a backpack propulsion unit that will be used on Space Shuttle flights. The manned maneuvering unit (MMU) training simulator allows astronauts to "fly missions" against a full scale mockup of a portion of the orbiter vehicle. Controls of the simulator are like those of the actual MMU. Manipulating them allows the astronaut to move in three straight-line directions and in pitch, yaw and roll. One possible application of the MMU is for an extravehicular activity chore to repair damaged tiles on the vehicle. McCandless is wearing an extravehicular mobility unit (EMU).

S83-40555 (15 October 1983) --- These five astronauts are in training for the STS-41B mission, scheduled early next year. On the front row are Vance D. Brand, commander; and Robert L. Gibson, pilot. Mission specialists (back row, left to right) are Robert L. Stewart, Dr. Ronald E. McNair and Bruce McCandless II. Stewart and McCandless are wearing Extravehicular Mobility Units (EMU) space suits. The STS program's second extravehicular activity (EVA) is to be performed on this flight, largely as a rehearsal for a scheduled repair visit to the Solar Maximum Satellite (SMS), on a later mission. The Manned Maneuvering Unit (MMU) will make its space debut on STS-41B.

S84-27023 (7 Feb 1984) --- This 70mm frame shows astronaut Bruce McCandless II moving in to conduct a test involving the Trunion Pin Attachment Device (TPAD) he carries and the Shuttle Pallet Satellite (SPAS-01A) partially visible at bottom of frame. SPAS was a stand-in for the damaged Solar Maximum Satellite (SMS) which will be visited for repairs by the STS-41C Shuttle crew in early spring. This particular Extravehicular Activity (EVA) session was a rehearsal for the SMS visit. The test and the actual visit to the SMS both involve the use of jet-powered, hand-controlled Manned Maneuvering Unit (MMU). The one McCandless uses is the second unit to be tested on this flight. Astronaut Robert L. Stewart got a chance to work with both MMU's on the two EVA's.

CAPE CANAVERAL, Fla. -- At the Kennedy Space Center Visitor Complex in Florida, a display inside the "Space Shuttle Atlantis" facility features an extravehicular activity mobility unit -- the space suit worn by spacewalking astronauts during the shuttle program. Attached to the back is a Manned Maneuvering Unit jet pack worn by astronauts during untethered spacewalks on STS-41B and STS-41C. The new $100 million facility will include interactive exhibits that tell the story of the 30-year Space Shuttle Program and highlight the future of space exploration. The "Space Shuttle Atlantis" exhibit is scheduled to open June 29, 2013.Photo credit: NASA/Jim Grossmann

S84-27562 (7 Feb. 1984) --- Astronaut Bruce McCandless II, one of two 41B mission specialists participating in a historical Extravehicular Activity (EVA), is a few meters away from the cabin of the Earth-orbiting space shuttle Challenger in this 70mm frame. This Extravehicular Activity (EVA) represented the first use of a nitrogen-propelled, hand-controlled device called the Manned Maneuvering Unit (MMU), which allows for much greater mobility than that afforded previous spacewalkers who had to use restrictive tethers. Robert L. Stewart later tried out the MMU McCandless is using here, and the two of them tested another similar unit two days later. Inside the spacecraft were astronauts Vance D. Brand, commander; Robert L. Gibson, pilot; and Ronald E. McNair, mission specialist. Photo credit: NASA

S84-27017 (7 Feb. 1984) --- Astronaut Bruce McCandless II, one of two 41-B mission specialist, participating in a historical Extravehicular Activity (EVA), is a few meters away from the cabin of the Earth-orbiting space shuttle Challenger in this 70mm frame. This EVA represented the first use of a nitrogen-propelled, hand-controlled device called the Manned Maneuvering Unit (MMU), which allows for much greater mobility than that afforded previous spacewalkers who had to use restrictive tethers. Robert L. Stewart, mission specialist, later tried out the MMU McCandless is using here. The two of them tested another similar unit two days later. Inside the spacecraft were astronauts Vance D. Brand, commander; Robert L. Gibson, pilot; and Ronald E. McNair, mission specialist. Photo credit: NASA