A Heck of a Leap: When Bruce McCandless Became the First Human Satellite

NASA astronaut Bruce McCandless II during his flight test of the Manned Maneuvering Unit (MMU) in February 1984 (NASA)
NASA astronaut Bruce McCandless II during his flight test of the Manned Maneuvering Unit (MMU) on February 7, 1984 (NASA)

On Feb. 7, 1984, NASA astronaut Bruce McCandless II became the first “human satellite” when he tested the Manned Maneuvering Unit during STS-41B. Propelled via 24 small nitrogen-powered thrusters, the MMU allowed McCandless (who was instrumental in developing the Unit at Lockheed Martin) to travel freely through space. In the iconic photo above McCandless is seen floating against the blackness of space, 320 feet (98 meters) away from the Challenger orbiter…and 217 miles (350 km) above the Earth!

A former U.S. Navy captain, McCandless was 46 years old when he performed his historic tether-free EVA.

“May well have been one small step for Neil, but it’s a heck of a big leap for me!”
– STS-41B Mission Specialist Bruce McCandless II, Feb. 7, 1984

During the STS-41B mission both McCandless and fellow crew member Robert Stewart tested the MMUs during two EVAs. The Units would later be used on two more Shuttle missions to retrieve and repair malfunctioning satellites. (Only one of these missions would see successful use of the Unit.)


After the 1986 Challenger disaster and the re-evaluation of procedures that resulted, NASA decided that the MMU wasn’t really necessary. The ability of an orbiter to get close enough to a satellite to pluck it from orbit using its robotic Canadarm made the MMU redundant and too much of a personal risk for the astronauts.

Still, for a brief time humans had a way of flying free above the world. And that’s something to be remembered (and hopefully one day repeated!)

The MMU used by McCandless is now on display at the National Air and Space Museum’s Udvar-Hazy Center in Chantilly, VA.

Read more about the MMU here and here, and watch the video below for more information on McCandless’ flight and the MMU’s usage.

Sources: NASA and Smithsonian Air & Space