Astronauts to camp out in space station airlock

CAPE CANAVERAL, Fla., Apr 4: There will be no bonfires or early morning fishing trips, but two astronauts aboard the International Space Station will attempt an orbital camp-out.

Station commander Bill McArthur and the incoming US crewmember, Jeffrey Williams, have stashed their sleeping bags and personal gear in the station's US airlock module for an overnight stay yesterday. 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 quickly.

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 Yesterday.

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.

Reuters