The unfurling of the International Space Station's final pair of solar array wings has begun. "Houston, we see good motion," shuttle Discovery commander Lee Archambault reported to NASA's Mission Control Center at 11:06 a.m.
Discovery mission specialist John Phillips pressed a button to begin extending a mast that will gradually unfold the first pleated array, opening it up like a road map. The plan is to extend the first array, referred to as "1B," to 49 percent of its length, or about 56 feet.
The process will move very slowly, with astronauts on the station and shuttle watching a dozen camera views and looking out windows to ensure that the array folds don't stick together as they are lifted - a problem known as "stiction."
The arrays, which will each extend 115 feet, have been packed in boxes to a thickness of inches for years - 5.5 years for one, and nearly eight years for the other. Their polymers and chemical coatings could be prone to sticking together.
To prevent that problem, the deployment will proceed gradually and pause halfway to let the arrays bake in the sun for about 30 minutes. Phillips will hit an abort button if anyone sees any sign of a problem.
If all goes well, deployment of both wings will take about 4.5 hours.
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