To Fly Free in Space
Explanation:
At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless
II was further out than anyone had ever been before.
Guided by a
Manned Maneuvering Unit (MMU), astronaut McCandless,
pictured above, was floating free in space.
McCandless and fellow
NASA astronaut
Robert Stewart were the first to experience such an
"un
tethered
space walk"
during
Space Shuttle mission
41-B in
1984.
The
MMU works by shooting jets of
nitrogen
and has since been 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 replaced with the
SAFER backpack propulsion unit.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
