By finishing the electrical work, the spacewalkers set the stage for installation of more solar arrays and science modules, including those being supplied by international partners.
For a second time, flight controllers shut down about half of the stationís systems, including some lights, communication gear, ventilation fans and back-up computers as the third spacewalk of Discoveryís mission began at 1:25 p.m. CST. Curbeam and Williams finished their rewiring tasks at nearly the same time posted by Curbeam and Mission Specialist Christer Fuglesang on Thursday. By 3:18 p.m., controllers were powering up the second half of the stationís new power grid and cooling systems.
The spacewalkers also installed a robotic arm grapple fixture and positioned three bundles of Russian debris shield panels outside the Zvezda service module before moving on to their P6 solar array panel 4B retraction work. The debris panels will be installed on a future spacewalk.
Then, using maneuvers dubbed the "Beamer Shake" and the "Suni Shake," the spacewalkers tackled grommets and guide wires that have been preventing a full retraction of the array since Wednesday. Curbeam and Williams stationed themselves on opposite sides of the array and took turns shaking the array blanket box while the crew inside the station reeled in the array one bay at a time. Curbeam shook the blanket 19 times, and Williams shook it 13 times. The crew inside the station, coordinating with flight controllers on the ground, initiated eight retraction cycles.
As a result of their combined efforts, the array is now 65 percent retracted, with only 11 bays still deployed. The 7 hour, 31 minute spacewalk concluded at 8:56 p.m.
In the midst of the excursion, Mission Control informed the crew that managers had decided to extend Discoveryís mission one day to allow a fourth spacewalk. Curbeam and Fuglesang will venture outside Monday in an attempt to complete retraction of the array and collect additional information that could prove useful when the opposite side of the array is retracted on the next shuttle mission, STS-117, in March. The extended flight plan preserves a late inspection of Discoveryís heat shield after it undocks from the station. Discovery is scheduled to land at Kennedy Space Center on Friday afternoon.
Discoveryís crew is scheduled to go to sleep at 12:17 a.m. Sunday, and will awaken at 8:17 a.m. for a day devoted to cargo transfers and spacewalk preparations.