US: Two spacewalking astronauts replaced a broken steering device on the international space station yesterday and prepared for a possible new and untested venture to space shuttle Discovery's belly to fix its heat shield.
During the second of three spacewalks planned during their mission, astronauts Soichi Noguchi and Steve Robinson removed one of the station's four gyroscopes and replaced it with a new one.
The gyroscopes keep the outpost properly positioned in space without using the station's limited supply of propellant for rocket-thruster burns.
After unbolting the old gyroscope, Dr Robinson, the flight engineer, pulled it out and waited for Mr Noguchi, also an engineer, riding on the station's robot arm, to get into position to carry it away. "It's not easy for me to hold this rascal," Dr Robinson said, clasping the 300kg (660lb) mass.
Then, noting Mr Noguchi perched on the arm, he joked: "You've got a ticket to ride." Mr Noguchi deposited the gyroscope on to a holding rack while the new gyroscope was hauled into place on the station's truss.
The failed instrument was packed into the shuttle's cargo bay for engineers to analyse after the ship's return to earth.
Before returning to the shuttle's airlock, the astronauts prepared some tools that may be needed for an unscheduled heat shield repair during the third spacewalk tomorrow or possibly a fourth outing on Friday.
Nasa managers are trying to decide if Discovery's heat shield needs work before the shuttle attempts Nasa's first landing since the destruction of Columbia and the deaths of its seven astronauts in 2003. - (Reuters)