STS-41-B produced one of the most iconic photographs in the history of space exploration — astronaut Bruce McCandless floating alone in the void of space, untethered from any spacecraft, with nothing but the blue curve of Earth behind him. On February 7, 1984, McCandless became the first human to perform an untethered spacewalk, using the Manned Maneuvering Unit (MMU), a nitrogen-powered jetpack that allowed him to fly freely up to 320 feet from Challenger.

Space Shuttle Challenger launched from Kennedy Space Center’s LC-39A on February 3, 1984, carrying Commander Vance Brand, Pilot Robert Gibson, and Mission Specialists Bruce McCandless, Robert Stewart, and Ronald McNair. The crew’s primary objectives included testing the MMU, deploying two communications satellites, and practicing satellite retrieval techniques that would be needed for future repair missions.

McCandless had waited 18 years for his first spaceflight and had been developing the MMU concept since the 1960s. His historic untethered spacewalk lasted nearly six hours. Robert Stewart also tested the MMU during a second EVA. Together, the two spacewalks accumulated approximately 12 hours of EVA time. The MMU would later prove essential for the STS-51-A mission, which retrieved the very satellites that STS-41-B had failed to place in proper orbit.

The mission deployed two communications satellites — Westar VI and Palapa B-2 — but both suffered failures of their Payload Assist Module boosters and were stranded in useless low orbits. This setback led to the remarkable STS-51-A retrieval mission later that year. STS-41-B also achieved another first: it was the first Shuttle mission to land at Kennedy Space Center, touching down on the KSC Shuttle Landing Facility runway rather than the dry lakebed at Edwards Air Force Base. This demonstrated that the orbiter could land precisely enough for the shorter, narrower KSC runway.