June 1, 2001

 Station residents will not make spacewalk to fix balky arm

 By Steven Siceloff
 FLORIDA TODAY

 CAPE CANAVERAL - Astronaut Jim Voss and cosmonaut Yury Usachev will not
 replace a computer box on space station Alpha's robot arm during a
 spacewalk scheduled for June 8, NASA officials said today.

 The box was suspected of causing problems on the 57-foot-long arm, but
 analysts have all but ruled it out as a culprit in studies conducted over
 the past week.

 They are focusing instead on an electronic component inside the backup
 power and control system in the arm's shoulder joint. There is no spare
 joint on the station, but one is expected to arrive aboard shuttle
 Discovery in early August.

 The arm troubles have forced a postponement of the next two shuttle
 flights while engineers analyze causes and cures.

 Atlantis, which could launch as early as July 2, will carry an airlock
 for the station. Because of its place on the station, Alpha's arm is the
 only device that can lift the airlock out of the cargo bay and plug it
 into the outpost.

 NASA is exploring several options for installing the arm.

 Under consideration: everything from simple computer programs that tell
 the arm's computers to ignore the problem to planning a way for
 spacewalking astronauts to move the arm around by hand.

 Station robotics chief Aaron Goldenthal said evaluations also are under
 way to determine whether the arm can be maneuvered without involving the
 troublesome joint.

 Flight Director John Curry said managers could sign off on a backup plan
 that leaves the airlock on the end of the arm when Atlantis heads for
 home. The new module must be close enough to the station for spacewalkers
 to connect power and data cables between it and the station.

 "If we can't make either of those happen, we'll start to discuss fixing
 that joint," Curry said.

 For Voss and Usachev, the June 8 exercise will be limited to 40 minutes
 of working inside the station.

 Wearing spacesuits, Usachev and Voss will depressurize a small segment of
 the station and move a docking cone from one hatch on Zvezda to another.

 Astronaut Susan Helms will watch from other parts of the station.

 Voss said Friday he does not have any concerns about doing the work while
 clothed in a Russian Orlan spacesuit.

 "It's not a terribly difficult task," Voss said.

 Letting the pair move outside the station to install a new arm computer
 would add more than five hours to the activity.

 "We do what the team tells us to do," Helms said.