Who made the first untethered free flight in space using the MMU?

Bruce McCandless II made the first untethered free flight in space using the MMU.

McCandless achieved the milestone on February 7, 1984, during Challenger’s STS-41-B mission. Wearing the Manned Maneuvering Unit, he moved away from the shuttle and became the first person to fly freely in space without a physical tether connecting him to a spacecraft.

The flight was a planned demonstration, not an improvised stunt. McCandless and fellow mission specialist Robert L. Stewart checked the MMU’s maneuvering controls, flew away from and back toward Challenger, practiced rendezvous and docking movements, and gathered engineering data. McCandless reached a distance of roughly 150 nautical miles above Earth while the shuttle orbited at about 17,500 miles per hour.

Stewart also flew the MMU on the same mission, so he is sometimes mistakenly credited with the first free flight. The distinction belongs to McCandless because he performed the first untethered excursion. His iconic image, arms extended against the darkness of space, became one of the most recognizable photographs in human spaceflight history.