Alpha crew girds for added challenge in spacewalk

The Alpha crew: Jim Voss, left, Yury Usachev, center, and Susan Helms

By Richard Stenger
CNN

(CNN) -- The residents of the international space station are expected to make their first foray into the vacuum of space soon. And an unforeseen technological twist could add plenty of excitement and time to the excursion.

A cosmonaut and astronaut expect to don their spacesuits next week to position a docking cone in the Zvezda service module while a compartment on the module is depressurized.

The move, the first internal spacewalk on space station Alpha, will prepare the orbiting outpost for the arrival of a Russian docking module during the summer.

But a problem with a new robotic arm, delivered last month by a space shuttle crew, could mean that the duo performs the first external spacewalk on the same day.

INTERACTIVE INSIDE ISS     MESSAGE BOARD Human spaceflight

A backup electronics box near the elbow of the Canada-built arm failed to work properly in recent tests. A house call on the outside of Alpha could be the only way to fix it, according to space station managers.

Scheduled for June 8, the internal spacewalk could be extended several hours to allow Russian Yury Usachev and American Jim Voss to go outside and replace the faulty box with a spare onboard.

But the outside venture could be avoided if mission engineers manage to mend the $1 billion broken arm from the ground.

"We're still working on exactly what's wrong. We could do a software patch to get through the problems we've seen," station flight director Bob Castle told reporters Friday.

The 57-foot (17-meter) robotic arm, a jointed appendage designed to travel like an inchworm, connecting to various computer and power ports all over Alpha, is needed to attach an airlock to the station.

The installation is scheduled to take place in late June when the space shuttle Atlantis brings the airlock. The Atlantis crew expects to conduct three spacewalks to install it.

Composed of two cylindrical chambers, the airlock will serve as the primary exit and entrance port for Alpha, currently housing its second three-person crew.

While Alpha residents have yet to venture outside, such trips could become commonplace during future construction on the complex, which the United States, Russia and other partners hope to complete by 2006.

"It's like any other technological project. Things are going to break down. We are going to have to replace things. We are going to have to have spare parts and install those spares," Castle said.