April 3, 2006

Astronauts to camp out in space station airlock

CAPE CANAVERAL, Florida (Reuters) - There will be no
bonfires or early morning fishing trips, but two astronauts
aboard the International Space Station will attempt an orbital
camp-out on Monday night.

Station commander Bill McArthur and the incoming U.S.
crewmember, Jeffrey Williams, have stashed their sleeping bags
and personal gear in the station's U.S. airlock module for an
overnight stay. The astronauts plan to have fun, but that is
not the point of the exercise.

Once the men are sealed inside the chamber, the pressure in
the airlock will be lowered to test a new procedure for
preparing astronauts for spacewalks from the station.

Before leaving the outpost, astronauts breathe pure oxygen
to remove nitrogen from their bloodstreams. In the vacuum of
space, nitrogen in the body can lead to a dangerous condition
called "the bends," which can afflict divers who surface too

Lowering the airlock's ambient air pressure cuts the amount
of time astronauts need to breathe pure oxygen.

The station is normally pressurized at 14.7 pounds per
square inch, or psi, the same as atmospheric pressure on Earth.
During the camp-out, the station's onboard software will be
tested to see if it can maintain the pressure at 10.2 psi.

"Upcoming shuttle crews hope to use this camp-out inside
the airlock to reduce the amount of oxygen pre-breathe time
they do before ... going out," McArthur said during an
in-flight press conference Monday.

McArthur and his flight engineer, Valery Tokarev, are
scheduled to return to Earth this weekend after a six-month
stay in space. They are being replaced by Williams and
commander Pavel Vinogradov, who arrived at the outpost, along
with visiting Brazilian astronaut Marcos Pontes, aboard a
Russian Soyuz capsule on Saturday.

Pontes will return with McArthur and Tokarev.

NASA hopes to add a third permanent station crewmember with
the launch of European astronaut Thomas Reiter aboard space
shuttle Discovery in July. The station crew was cut to two
while shuttle flights were suspended following the 2003
Columbia accident.