Bruce McCandless floats solo during the STS-41B Challenger mission in February 1984 (NASA).
It is an iconic image from the 80s. An astronaut floats alone with the Earth under his feet. There is nothing around him. He appears to be flying freely through space, although his face cannot be seen because he has the golden visor down, a feature that makes him the perfect symbol of humanity’s advancement in the conquest of space. But the protagonist of the photo was not anonymous and had a name: Bruce McCandless II, an astronaut who on February 7, 1984, became the symbol of a generation when he walked away from the Challenger shuttle using his MMU powered backpack during the STS-41B mission. . . And, as often happens in these cases, the photo does not tell us the whole story, or what is worse, it tells us a biased story.
First, because despite common belief, McCandless was not the first astronaut to go on a spacewalk without any connection to the spacecraft. That honor goes to Russel “Rusty” Schweickart, who first tested the A7L suit with the new Life Support Backpack (PLSS) in low orbit in March 1969 during the Apollo 9 mission. of the lunar module, but the twelve Apollo astronauts who between 1969 and 1972 walked on the Moon without being attached to their spacecraft did. At the time, these offline extravehicular activities represented a complete revolution with respect to the spacewalks of the Gemini missions in which the astronaut was attached to his ship by means of an umbilical that provided oxygen, electricity, communications and security.
Astronauts may be able to use their own legs as a propulsion system on the Moon, but in weightlessness things change. However, as early as January 1969 cosmonauts Yevgueni Hrunov and Alexéi Yeliseyev carried out an extravehicular activity from Soyuz 5 to Soyuz 4 in low orbit using Yastreb suits with autonomous life support backpacks and, therefore, did not require umbilical’s to oxygen and electricity. In the 70s and early 80s, spacewalks were carried out from the Soviet Salyut stations in Orlán suits and from the US shuttle with EMU diving suits, all of them equipped with autonomous life support systems (not at the Skylab station, in which curiously umbilical’s were used for the EVAs). But in all these spacewalks the astronauts and cosmonauts used some type of safety cable to prevent them from flying off and getting lost in orbit beyond rescue.
The key was to design some microgravity maneuvering system. In this regard, McCandless was also not the first to use a maneuvering device to move through space. In the first American EVA in June 1965 Ed White already used a gas pistol to move – without much success – called the HHMU (Hand-Held Maneuvering Unit). Shortly thereafter, in June 1966, Eugene Cernan unsuccessfully tried to use the AMU (Astronaut Manoeuvring Unit) backpack during the Gemini 9 mission. In 1973 the astronauts of Skylab crews 3 and 4 used the ASMU (Automatically Stabilized Maneuvering Unit) backpack – also known as M-509 or AME (Astronaut Maneuvering Equipment) -, the predecessor of the MMU, although, yes, inside the spacious Skylab space station. What McCandless was the first to do was use a jetpack in low orbit without any connection to his ship to get away with it. It is always said that a pressure suit is a small spaceship, but in reality it is missing one of the most important systems: propulsion. With his MMU backpack, McCandless became a real miniature spaceship.