To Fly Free in Space
What would it be like to fly free in space?
At about 100 meters from the cargo bay of the
space shuttle Challenger,
Bruce McCandless II was living the dream --
floating farther out than anyone had ever been before.
Guided by a
Manned Maneuvering Unit (MMU), astronaut McCandless,
pictured, was
floating free in space.
McCandless and fellow
NASA astronaut
Robert Stewart were the first to
experience such an
"untethered space walk"
during Space Shuttle mission
41-B in
1984.
The MMU worked by shooting jets of
nitrogen
and was used to help deploy and
retrieve satellites.
With a mass over 140 kilograms, an
MMU is heavy
on Earth,
but, like everything, is weightless when drifting in orbit.
The MMU was later replaced with the
SAFER backpack propulsion unit.