Shuttle countdown to begin Thursday

CAPE CANAVERAL, Fla., Aug. 21 (UPI) -- NASA is set to begin the countdown for the Florida launch of the space shuttle Atlantis' mission to the International Space Station at 6 p.m. EDT Thursday.

The flight will mark resumption of ISS construction, started in 1998 but halted in 2003 after the loss of space shuttle Columbia and the death of its crew.

The NASA Kennedy Space Center launch team will conduct the countdown that includes 27 hours, 24 minutes of built-in hold time leading to a preferred launch time at 4:30 p.m. Sunday. The launch window for that day extends an additional five minutes.

The mission -- the 116th space shuttle flight, the 27th flight for Atlantis and the 19th U.S. flight to the International Space Station -- is to last 11 days, with a landing at Kennedy about 12:02 p.m. EDT Sept. 7.

The STS-115 crew is Commander Brent Jett, pilot Chris Ferguson, and mission specialists Joe Tanner, Dan Burbank, Heide Stefanyshyn-Piper and Canadian astronaut Steve MacLean.

They are to, among other things, deliver and install a 17.5-ton integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics.