Astronaut Bruce McCandless II, STS-41B mission specialist, uses his hands to control his movement above the Earth, and just few meters away from the space shuttle Challenger, during the first-ever spacewalk without tethers and umbilicals. Source: NASA

The first astronaut to fly in space untethered died on December 21, 2017, at the age of 80. According to NASA, Captain Bruce McCandless II (U.S. Navy, retired) was a mission specialist on the STS-41B and STS-31 Space Shuttle missions in 1984 and 1990, respectively, and is best known for being the first person to use the Manned Maneuvering Unit (MMU) to fly alongside the Shuttle without a safety line. He also served as the Mission Control communicator for Neil Armstrong and Buzz Aldrin's moonwalk on the Apollo 11 mission.

On STS-41B in 1984, he performed the famous spacewalk, captured in the video above, and on STS-31 in 1990 he helped deploy the Hubble Space Telescope.

Of his famous spacewalk, he wrote in 2015: "My wife [Bernice] was at mission control, and there was quite a bit of apprehension. I wanted to say something similar to Neil [Armstrong] when he landed on the moon, so I said, 'It may have been a small step for Neil, but it’s a heck of a big leap for me.' That loosened the tension a bit."

Astronaut McCandless logged more than 312 hours in space, including four hours of flight time using the MMU.