HAUNTED by the science-fiction image of an astronaut drifting helplessly in
space, NASA last week successfully tested a miniature jet pack that will let
drifting astronauts return to the International Space Station under their own
power.
The jet pack unit, called SAFER, is a backup for the tethers that will hold
astronauts in place while they work outside the ISS. The snag is that SAFER
works only with American spacesuits, not Russian ones. Yet Russian suits are the
only type that can be used on the ISS until a module with a large airlock is
installed sometime next year.
The Russian suits are also easier to put on and move around in. 鈥淲e want to
be able to use the Russian spacesuits,鈥� says a NASA spokesman.
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The agency wants to pay Russia to develop a version for its spacesuits, but a
spat with Congress is delaying this. Congress is waiting for assurances from
NASA that the cash it intends paying the Russian Aviation and Space Agency is
for crucial life-saving safety equipment. This is a proviso of the Iran Non
Proliferation Act 2000, which is designed to stop military aid reaching Tehran
through Russia.
NASA wants the jet packs because a broken tether is much more serious for ISS
astronauts than for space shuttle crew. While the shuttle can chase and rescue a
wayward astronaut, the ISS is too large and unwieldy to be able to do this. The
new jet packs 鈥渉ave got to be able to help the astronauts rescue themselves鈥�,
says NASA.
Astronauts Jeff Wisoff and Michael Lopez-Alegria successfully tested SAFER
(the name stands for 鈥渟implified aid for extravehicular activity rescue鈥�) in a
space shuttle鈥檚 payload bay last week, though NASA has yet to analyse the test
data in detail. The pack, which is attached to the base of the life-support
backpack on American suits, has 24 small jets that fire pressurised nitrogen
gas. Astronauts control the jets with a joystick.
The ride is hardly fast and furious. SAFER is designed to bring wayward
astronauts home at a leisurely 0.5 metres per second. It has a top speed of 3
metres per second, similar to a gentle jog.