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28 years ago today, NASA astronaut Bruce McCandless left the relative safety of Challenger’s payload bay and went untethered into orbit around Earth, venturing farther than anyone ever before.
The historic photo above was taken when McCandless was 320 feet from the orbiter — about the length of an American football field, or just shy of the width of the International Space Station.
The free-flying endeavor was possible because of McCandless’ nitrogen-powered jet-propelled backpack, called a Manned Maneuvering Unit (MMU). It attached to the space suit’s life-support system and was operated by hand controls, allowing untethered access to otherwise inaccessible areas of the orbiter and was also used in the deployment, service and retrieval of satellites.
The MMU used a non-contaminating nitrogen propellant that could be recharged in the orbiter. It weighed 140 kg (308 lbs) and has a built-in 35mm camera.
After the Challenger disaster, the MMU was deemed too risky and was discontinued. But for a brief period of time in the early ’80s, humans had the means for really “soaring to new heights”.