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.

CAPE CANAVERAL, Fla. - NASA senior managers Tuesday completed a detailed review of space shuttle Discovery's readiness for flight and selected Oct. 23 as the official launch date. Commander Pam Melroy and her six crewmates are scheduled to lift off at 11:38 a.m. EDT on the STS-120 mission to the International Space Station.

Tuesday's meeting included a discussion about concerns raised by the NASA Engineering and Safety Center regarding the reinforced carbon carbon on three of Discovery's wing leading edge panels. This issue initially was brought before the Space Shuttle Program during a two-day, preliminary review held last week to assess preparations for Discovery's mission.