The Space Shuttle began orbiting in 1981. It brought the promise of a more efficient space program in the future, for its primary purpose was to provide a facility for NASA engineers to repair malfunctioning satellites.
Replacing a satellite was (and still is) not particularly cheap, so at least proper maintenance could cut down the expense to a reasonable extend.
Space Shuttle as a service station was a much-needed improvement. However, still, astronauts doing the repairs required a “wearable” propulsion system to ensure good mobility while floating in outer space.
A new device known as Manned Maneuvering Unit (MMU) to be attached to spacesuit was subsequently developed to support operations.
Martin Marietta Corporation acquired the rights to design and build MMU. The result was a 300-pound apparatus powered by an 852 Watts battery, allowing for 6 hours of runtime and equipped with 24 nitrogen thrusters.
MMU featured hand controllers mounted on the armrests. Sent to space in the payload bay of the Challenger on February 3, 1984, Mission Specialist Bruce McCandless successfully utilized the MMU for the first time in history four days later.
10 /10 Long Time In The Making
The fourth flight of Space Shuttle Challenger launched on February 3, 1984, from the Kennedy Space Center in Florida. At the top of the priority list in the mission directive was the deployment of two communication satellites.
Following close at the second place was MMU maiden voyage. Before launch, MMU had been a work in progress since decades earlier.
It still required some tweaking just weeks before the first real-world run. The person picked to pilot the performance test was Bruce McCandless, who was also involved in developing the device propulsion system.
9 /10 A Space First
Four days after launch, it was time to take the MMU out from the Challenger to outer space.
Since the MMU had its controller and propulsion system, the planned free flight was untethered, unlike any other astronaut had ever done before.
The device had its final preparation doing some maneuvers inside and above the Challenger.
Finally, Bruce McCandless “took off” and went free flying. He covered a distance of just 300 feet away from the space shuttle.
Everything, including the controller, sensors, and thrusters, ran without a hitch. It was a task completed with flying colors.