SUBMITTED BY ARTHUR N1ORC - AMSAT A/C #31468

*STS-118 Astronauts to Go Spacewalking Today * Image above: The International Space Station's robotic arm moves the S5 truss. Image: NASA TV TO VIEW IMAGE GO TO:http://www.nasa.gov/mission_pages/shuttle/main/index.html

The STS-118 and Expedition 15 crews are preparing for today’s spacewalk to install the Starboard 5 (S5) truss onto the International Space Station. STS-118 Mission Specialists Rick Mastracchio and Dave Williams are slated to begin their orbital stroll at 12:31 p.m. EDT.(1631 UTC)

The S5 will be attached to the Starboard 4 segment about 1:56 p.m. with the spacewalking duo guiding station robot arm operator Charles Hobaugh, STS-118’s pilot, as he moves the S5 to the attachment point. The spacewalkers will then bolt it into place and make power and data connections.

The other major task during the spacewalk is the retraction of a radiator on the Port 6 (P6) truss. After the radiator is folded, Mastracchio and Williams will secure it. The P6 will be relocated from atop the station to the end of the Port 5 truss during a future mission.

The excursion is scheduled to last 6.5 hours. Mission Specialist Tracy Caldwell is the spacewalk coordinator, and Expedition 15 Flight Engineer Clay Anderson is assisting Hobaugh at the controls of the station’s Canadian-built robotic arm.

Meanwhile, the Station-to-Shuttle Power Transfer System, which was activated after Friday’s docking, will be shut down during the spacewalk. The transfer system may allow Space Shuttle Endeavour and the STS-118 crew to stay at the station longer. A decision on a possible mission extension is expected to be made Sunday.

Animations: + S5 Truss Overview javascript:watchNASAOnDemandTV('http://mfile.akamai.com/18566/wmv/etouchsyst2.download.akamai.com/18355/wm.nasa-global/STS-118/S5_OV.asx') | + S5 Truss Installation javascript:watchNASAOnDemandTV('http://mfile.akamai.com/18566/wmv/etouchsyst2.download.akamai.com/18355/wm.nasa-global/STS-118/S5_Install.asx')

*Mission Information* + View Barbara Morgan Video javascript:watchNASAOnDemandTV('','http://mfile.akamai.com/18565/rm/etouchsyst2.download.akamai.com/18355/real.nasa-global/sts-118/STS118_Morgan.ram','http://mfile.akamai.com/18566/wmv/etouchsyst2.download.akamai.com/18355/wm.nasa-global/STS-118/STS118_Morgan.asx') + STS-118 Mission Overview http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts118/index.html + STS-118 Fact Sheet (900 Kb PDF) http://www.nasa.gov/pdf/184910main_sts118_factsheet4.pdf + STS-118 NASA TV Schedule http://www.nasa.gov/multimedia/nasatv/mission_schedule.html + STS-118 Briefing Animations http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts118/multimedia/sts118_anim_07102007.html + STS-117 Mission Archive http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts117/main/index.html