Saturday, July 25, 2009

Live in orbit: Endeavour crew enjoying day off

Blogger update, 7 p.m.: Engineers are still troubleshooting a problem with the U.S. system that scrubs carbon dioxide from the station's air. The outpost is relying on the Russian segment's system. Flight controllers told station crew members to alert flight surgeons of any potential symptoms from carbon dioxide build-up, but were not concerned about current levels.

Crews on board the International Space Station are enjoying a day of light duty, relaxation, exercise and time to catch up with family and friends on the ground.

"I think we needed it," shuttle Endeavour commander Mark Polansky told mission controllers in Houston.

An assembly designed to remove carbon dioxide from the Destiny lab's air temporarily shut down after temperatures on one of two related heaters rose above normal, but the problem isn't expected to be serious.

This morning, shuttle Endeavour's crew of seven - shown above without mission specialist Koichi Wakata - took time to answer questions about their mission from three media outlets.

"It's been a real challenge," said mission specialist and lead spacewalker Dave Wolf. "Very complex. Didn't go all according to schedule, but we're back on track."

Also in progress today is planning for the mission's fifth and final spacewalk on Monday,expected to last 6.5 hours.

Astronauts involved in the work, including spacewalkers Chris Cassidy and Tom Marshburn, began a meeting with planners on the ground at 1 p.m.

A preliminary plan included the following sequence of tasks:

- Adjusting protective thermal covers on the Canadian-built Special Purpose Dexterous Manipulator robot arms, known as the SPDM or Dextre. The arms could be used to install spare parts on the station without a spacewalk.

- Rewiring cables at the station's Z1 truss segment so that two gyroscopes each have their own power source. Four gyroscopes control the station's orientation in space. If that power source failed, it would knock out half of the gyroscopes, so the change reduces the impact of such a failure.

- Installing video equipment on the new "porch" installed earlier in the mission on the Japanese science lab called Kibo, or "hope." The views are needed to prepare for the arrival of a new Japanese robotic resupply spacecraft later this year.

- Attach devices on the Starboard 3 truss segment that will hold large spare parts outside the station. The parts will be needed to extend the station's life after the space shuttle's planned retirement next year.

Mission controller report that all six new solar array batteries installed during the mission's third and fourth spacewalks are holding power and expected to be integrated into the station power system soon.

What's next? Around 5 p.m. today, the 13 astronauts on the station will beam down a video called "The Partnership of the International Space Station." It will share thoughts on the record number of people on board one spacecraft, which include representatives from all of the station's major international partners: the United States, Russia, Japan, Canada and Europe.

You can watch it here - just click the NASA TV still image on this page to launch a viewer.

The crew plans to go to sleep around 8:30 p.m. EDT and wake up Sunday around 4:30 a.m. EDT.

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