A two-orbit test of the International Space Station's starboard solar wing rotary mechanism got off to a smooth start this morning as NASA aimed to determine whether spacewalking repairs to the joint worked as intended.The 10-foot-diameter gear started turning just before 5:55 a.m. after specialists beamed up computer commands from NASA's Mission Control Center in Houston. No motion could be seen on downlink TV, but the joint had rotated 30 degrees without major problems before NASA broke away for another showing of Flight Day 11 Highlights.
The joint is designed to turn a single set of starboard solar wings like a steamboat paddlewheel as the station circles Earth, making one complete 360-degree revolution every 90-minute orbit.
NASA Mission Commentator John Ira Petty reported that the joint's power consumption was within specifications, albeit a little higher than tests with its portside twin. There were no reports of high vibrations.
The starboard joint was placed in a stationary position in September 2007 after engineers noted higher-than-normal power consumption and higher-than-allowable vibrations during operation. Inadaequate lubrication caused internal parts to gring, creating metal shavings to foul the joint.
Endeavour astronauts Heidemarie Stefanyshyn-Piper, Stephen Bowen and Shane Kimbrough cleaned and lubricated the joint and replaced 11 of its 12 bearing assemblies during four spacewalks spaced out over the past week. The repair work was finished Monday.
The test is considered key to plans to expand station crew size to six next May. NASA and its international partners would like to restore as much power-production capability as possible to maximize scienctific research on the station.
You can watch mission activities unfold here in The Flame Trench. Simply click the NASA TV box at the righthand side of the page to launch our NASA TV viewer and round-the-clocl coverage of the STS-126 mission.
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