NASA STS-119 Report #11 Friday, March 20, 2009 – 8 p.m. CDT

HOUSTON – The International Space Station has its final pair of solar panels stretching 240 feet tip to tip after a lessons-learned flawless deploy earlier Friday. The station now has nearly an acre’s worth of U.S. arrays producing 120 kilowatts of usable electricity – doubling the amount available for science operations to 30 kilowatts.

Even before the crew awoke Friday, the protective blanket box latches were released and the arrays were deployed slightly to prepare for the deploys that began one wing at a time just after 10 a.m. The two-stage extension took just under an hour for each and was completed at 12:17 p.m. when the second array was unfurled to its full length of 115 feet.

Four pair of arrays were attached to the station in December 2000, September 2006, June 2007 and March 2009 bringing the total surface area to 38,400 square feet, or .9 acre. (1 acre = 43,500 sq ft)

With all crew watching for any problems from various windows and via several camera views, the arrays were deployed by the book on the strength of engineering procedures refined after problems with deploy and retraction occurred on previous arrays due to a phenomenon known as “stiction,” which simply means the accordion-like solar cells stick together until warmed properly.

After deploy, Expedition 18 Commander Mike Fincke and STS-119 Mission Specialist Sandy Magnus turned their attention to the replacement of a failed distillation unit which is part of the elaborate water purification and recycling system on the station. The failed unit will be returned aboard Discovery for analysis after the shuttle mission ends.

This evening, Mission Specialists Steve Swanson and Joseph Acaba will prepare the Quest airlock for their spacewalk set to begin just before noon Saturday. The spacewalk will focus on preparing worksites for future missions including Endeavour’s STS-127 mission and the arrival of the newest cargo vehicle – the Japanese H-II Transfer Vehicle (HTV).

Both crews head to bed between 10 and 11 p.m. and will be awakened at 6:43 a.m. Saturday.

The next status report will be issued after crew wake up, or earlier if events warrant.