SUBMITTED BY ARTHUR N1ORC - AMSAT A/C 31468

Oct. 17, 2007

Katherine Trinidad Headquarters, Washington 202-358-3749 katherine.trinidad@nasa.gov

George Diller Kennedy Space Center, Fla. 321-867-2468 george.h.diller@nasa.gov

NASA SET TO BEGIN SPACE SHUTTLE DISCOVERY COUNTDOWN OCT. 20

CAPE CANAVERAL, Fla. - NASA will start the launch countdown for space shuttle Discovery's STS-120 mission at 2 p.m. EDT Saturday, Oct. 20, at T-43 hours. The countdown includes 26 hours and 38 minutes of built-in hold time leading to a preferred launch time of approximately 11:38 a.m. on Tuesday, Oct. 23. The launch window extends an additional five minutes.

During the 14-day mission to the International Space Station, Discovery's crew will add the Node 2 module to the expanding station. Node 2, known as Harmony, will provide attachment points for European and Japanese laboratory modules to be installed later this year and early in 2008, respectively. The Discovery crew also will move the station's Port 6 segment of the station's backbone, or truss, and its solar arrays to a permanent position at the very end of the left side of the truss. The flight will include five spacewalks.

A detailed list of launch countdown milestones and times is available at:

http://www.nasa.gov/mission_pages/shuttle/news/index.html

This mission is the 120th space shuttle flight, the 34th flight for Discovery and the 23rd U.S. flight to the International Space Station. This mission includes the most number of spacewalks ever conducted while the shuttle is docked to the station.

For more information about the STS-120 crew and the mission to the space station, visit:

http://www.nasa.gov/shuttle

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