Astronauts complete first walk

Philippe Perrin spent more than seven hours outside

Spacewalking astronauts added a giant handgrip and cosmic-debris shields to the exterior of the International Space Station on Sunday.

Franklin Chang-Diaz and Philippe Perrin spent seven hours and 14 minutes working on the outside of the orbiting platform.

Two more spacewalks are planned this week for the current shuttle mission to the ISS.

These will be devoted to work on the outpost's robot arm. It will be given a new wrist joint and a base so that it can be moved around more easily to help with other construction tasks.

Safety excess

Chang-Diaz and Perrin used some of their time outside the ISS to photograph the four giant gyroscopes that keep the station stable in flight.

Seven astronauts, including Expedition Five, went up on Endeavour

One of the four desk-sized, 363-kilogramme (800-pound) gyros failed on Saturday and will have to be replaced.

But the American space agency thinks it may be a year before a shuttle can accommodate a new device - known as a Control Moment Gyro (CMG) - in its cargo bay.

The orbiting station can still function with two gyros, which are solar-powered.

And even if three failed, the ISS could use thrusters for stability, although this would use precious propellant that has to be flown up from Earth.

Rubbish return

"To lose a CMG is a big deal; this is a major component, but from a risk perspective right now we're in good shape," Flight Director Paul Hill told reporters.

"We are still one failure away."

Ten astronauts are on the station currently. Seven, including the platform's new resident crew - Expedition Five - came up on the Endeavour orbiter.

The three members of the outgoing ISS crew - Expedition Four - will return with the shuttle when it goes back to Earth on Monday, 17 June.

Those not involved in the spacewalk have been unloading about three tonnes of provisions and science gear brought up on Endeavour.

A similar load, including a lot of rubbish, must be packed up for the return flight.