Thursday, February 01, 2007

Sunita Williams takes 8-hour stroll in space


Indian American astronaut Sunita Williams and International Space Station commander Mike Lopez-Alegria went on a seven-hour, 55-minute space walk in the first of an unprecedented three outings in nine days.

The duo returned to their home in space through the Quest airlock at 4.39 am on Thursday after working on the reconfiguration of the station’s power and cooling systems, US space agency Nasa said. They are scheduled to take their second space walk February 4 and the third February 8.

While flight engineer Williams — wearing an all-white suit — reconfigured electrical connections, Lopez-Alegria — in the lead in a suit with red stripes — worked at the “rats’ nest”, an area near the base of the Z1 Truss with numerous fluid and electrical connections.

As the space walkers stood by, the ground control retracted the starboard radiator of the P6 Truss. After retraction, they installed six cable cinches and two winch bars to secure the radiator and then installed a shroud over it.

Williams and Lopez-Alegria then moved to the Early Ammonia Servicer on the P6 Truss. It provided a contingency supply of ammonia for the temporary Early Ammonia System. With the permanent cooling system working, it is no longer needed.

The space walkers removed one of two fluid lines from the servicer, which will be jettisoned this summer. Because of time constraints, the second will be removed on a subsequent space walk.

About 25 minutes of the space walk was spent in a “bakeout” after crewmembers had reentered the airlock. It was done as a precaution to prevent any possibility of ammonia from the fluid lines the space walkers had worked with entering the station.

The three space walks from the Quest airlock in US spacesuits and a Russian space walk scheduled for February 22 are the most ever done by station crew members during a single month.

They also will bring to 10 the total number of space walks by Lopez-Alegria, an astronaut record. Williams will have a total of four, the most ever by a woman.

Starting from scratch, it takes about 100 crewmember hours to prepare for a space walk. By doing space walks a few days apart, considerable crew time can be saved by not having to repeat some of those preparatory steps.

Already spanning an acre in orbit, the International Space Station this year will grow faster in size, power, volume and mass than ever before, significantly expanding its capabilities and setting new records for humans in orbit.

“This will be a challenging, but rewarding year for the station programme,” said Kirk Shireman, the deputy programme manager for the ISS.

“The station’s operations will grow both in orbit and on earth. As we launch new international components this year, we also will begin new flight control operations from facilities around the world.” In addition to control centres in the US, Russia and Canada, control centres for the station also will be activated in France, Germany and Japan for more effective observation. In 2007, Nasa and Russia plan to conduct as many as 24 space walks, more than has ever been done in a sin gle year.

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