Shuttle Discovery on Track for Thursday Launch

Shuttle Discovery Treks to Launch Pad for Next Mission
The space shuttle Discovery is settled on its Launch Pad 39B for launch of mission STS-116. Work crews hauled the orbiter and its launch stack to Pad 39B on Nov. 9, 2006 for a Dec. 7 launch. (Image credit: NASA/Amanda Miller.)

CAPECANAVERAL, Fla. - Launch countdown proceedings are going smoothly for theplanned Thursday liftoff of NASA's spaceshuttle Discovery.

"Oursystems are currently in great shape," said NASA test director StevenPayne in a status briefing here at the Kennedy Space Center. "Countdown isprogressing and we have no issue of consequence."

Thursday's plannedspace shot is set to commence at 9:35:47 p.m. EST (0235:47 Dec. 8 GMT). It willmark NASA's third shuttle launch this year and the agency's first night launchsince 2002. The shuttle's bright engine plume shouldbe visible to skywatchers along the eastern United States, weatherpermitting. [Click herefor a viewing map.]

The weatherforecast for launch day dipped slightly this morning in response to a coldfront that moved through Central Florida yesterday, but still stands at a 70percent chance of favorable flight conditions. Weather conditions are expectedto degrade significantly to 40 percent if Discovery's launch is delayed untilFriday or Saturday.

"Overall,the first day is the best day weather-wise," said NASA shuttle weatherofficer Kathy Winters. "Our main concern will be the ceiling on launch dayand winds the following two days."

The launchwindow currently runs from Dec. 7 to 17, but extensions are possible if shuttlemission managers approve Discovery for flight over the end-of-yearrollover.

"Someof the computers handle the New Year in a [different] way," Payneexplained. "Some of them go to Day 366 and some go to Day 1, so itrequires a reboot in order to get them all to talk to each other and besynchronized. Our preference is not to have to do that, but it's not ashowstopper."

Led by commanderMark Polanksy, the five-man, two-woman crewof STS-116 arrived here at Kennedy Space Center (KSC) Sunday afternoon andcountdown clocks for the launch began ticking at 11:00 p.m. Monday night (0400Dec. 6 GMT). The astronauts are performing a series of spacesuit fittings, medicalchecks and going over their orbiter and payload systems today, NASA officialssaid.

The STS-116crew is tasked with rewiringthe electrical grid of the ISS and delivering a new $11million portside piece of the orbital laboratory. Mission specialists SunitaWilliams will also relieve ESA astronaut ThomasReiter who has been aboard the station since July.

A built-in four-hourhold is scheduled for 3:00 p.m. EST (2000 GMT) today. The countdown will pickup again at 7:00 p.m. EST (0000 Dec. 7 GMT). Among the day's scheduled tasks aresome checks of the small explosive devices designed to separate the shuttlefrom its mobile launch pad, and the loading of cryogenic fuel that powersDiscovery's fuel cells.

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Staff Writer

Ker Than is a science writer and children's book author who joined as a Staff Writer from 2005 to 2007. Ker covered astronomy and human spaceflight while at, including space shuttle launches, and has authored three science books for kids about earthquakes, stars and black holes. Ker's work has also appeared in National Geographic, Nature News, New Scientist and Sky & Telescope, among others. He earned a bachelor's degree in biology from UC Irvine and a master's degree in science journalism from New York University. Ker is currently the Director of Science Communications at Stanford University.