Spacewalk ends; mission extended one day
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: February 13, 2008
Updated at 6:30 p.m. with resolution of computer glitch
Astronauts Rex Walheim and Hans Schlegel staged a successful six-hour 45-minute spacewalk today, replacing a nitrogen tank needed to maintain pressure in the space station's ammonia cooling system.
Mission managers, meanwhile, officially gave the shuttle Atlantis' heat shield a clean bill of health and decided to extend the mission one more day to give the crew additional time to activate the new Columbus research module. The extra day will be inserted Saturday with landing now targeted for around 9:06 a.m. on Feb. 20.
"Steve, a number of things to tell you here, all good news," astronaut Steve Robinson radioed shuttle commander Steve Frick from mission control in Houston. "Based on the inspection we've had so far, and all the other types of imagery, Atlantis' thermal protection system is currently cleared for entry. The programs came together and decided to add an additional one-day extension to your mission. ... You do have sufficient (carbon dioxide-absorbing lithium hydroxide) aboard the ship. We'll have to be checking on food, we're having our folks check on what was stowed, but we're going to need your input on that. We are looking forward to an O2 (oxygen) transfer (to the station), probably on flight day nine."
"Thanks very much for the big picture," Frick replied. "Great news, certainly we look forward to another day on the space station and happy to do whatever works best for the station and the station crew to put them in a good position when we leave. ... That's great news, we appreciate the heads up and also the good news that our TPS (thermal protection system) has been cleared for entry."
"That's exactly the intent of staying up an extra day, is getting Columbus that good head start with a trained crew," Robinson said.
The new Columbus module was attached to the space station Monday and within hours, European Space Agency engineers began working through a complex activation process. But they quickly ran into problems uplinking commands through the station's U.S. command and control system and into the computers inside Columbus. Late today, U.S. and European flight controllers decided the problem likely involved "stale commands" in a queue used by the station's primary U.S. computer system.
To flush out the queue, controllers shifted the active U.S. computer system into standby mode and designated a backup system as primary. Just before 6 p.m., engineers reported success, saying they finally were able to command the European computer systems. The Columbus activation process, which had been on hold, resumed but engineers decided to suspend the work overnight while the astronauts slept in case of any additional problems that might disturb their sleep or require their attention.
During today's spacewalk, Walheim and Schlegel successfully replaced a 550-pound nitrogen tank on the international space station's main solar power truss, installed four thermal covers on the keel pins used to secure the Columbus module in the shuttle's cargo bay for launch and worked to tie down micrometeoroid shields on the U.S. Destiny lab module. There were no problems of any significance and Schlegel, a German astronaut who became ill earlier in the mission and had to sit out a spacewalk Monday, appeared to have no problems today.
"It was great working with you today, you guys did an outstanding job," shuttle pilot Alan Poindexter, the spacewalk coordinator, radioed as Walheim and Schlegel returned to the station's airlock. "It really was a pleasure working with you."
"Awesome job, Dex, thanks for all the help," Walheim replied. "And thanks to the ground for all of our prepearion to get this done. It was really a great help in the execution."
This was the 103rd spacewalk devoted to station assembly and maintenance since construction began in 1998, the fourth for Walheim and the first for Schlegel. Total station EVA time now stands at 646 hours and 18 minutes with Walheim's cumulative total increasing to 28 hours and 58 minutes.
Walheim and astronaut Stan Love plan to stage a third and final spacewalk Friday to attach external instruments to the Columbus module and to move a faulty space station gyroscope back to Atlantis for return to Earth.