While in orbit 170 miles above Earth, Navy Captain Bruce
McCandless II became the first human being to perform
an untethered spacewalk, when he exits the U.S. space
shuttle Challenger and maneuvers freely, using a bulky
white jet pack of his own design.

McCandless orbited Earth in tangent with the shuttle at
speeds greater than 17,500 miles per hour—the speed
at which satellites normally orbit Earth—and flew up to
320 feet away from the Challenger. After an hour and a
half of testing and flying the jet-powered backpack and
admiring Earth, McCandless safely reentered the shuttle.

Bruce McCandless II
(June 8, 1937 – December 21, 2017)