Countdown clocks begin ticking for Discovery launch
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: April 2, 2010
With good weather expected, the shuttle Discovery's countdown began early Friday, setting the stage for a pre-dawn Monday launch to kick off a space station science and resupply mission.
The countdown began at 3 a.m. EDT, three hours after the successful launch of a Russian Soyuz spacecraft from Kazakhstan carrying a crew of three to the station. NASA Test Director Steve Payne said preparations for Discovery's launching "are going extremely well, there are no issues to report."
Liftoff is targeted for 6:21:23 a.m. Monday, roughly the moment Earth's rotation carries launch complex 39A into the plane of the International Space Station's orbit.
Kathy Winters, the shuttle weather officer, said the only concern is a chance of fog. But overall, the forecast for Monday and Tuesday calls for an 80 percent chance of acceptable conditions.
"Weather is looking very good right now at KSC," she said. "We've been experiencing some really nice weather, it's going to continue into launch day. The only concern we do have is for fog to form the morning of launch.
"Right now, we're forecasting a wind from the east. It's very light, though, and if
it happens to turn around and give us a land breeze, the temperatures could drop
enough to saturation and cause some fog in the area. We have a four-mile visibility
constraint for return-to-launch-site weather. So that's our primary concern for
launch and right now, we're going with a 20 percent chance of that occurring."
Early Sunday, during a long hold in Discovery's countdown, the Soyuz TMA-18 spacecraft launched from the Baikonur Cosmodrome in Kazakhstan Friday will dock with the space station.
Soyuz commander Alexander Skvortsov, Mikhail Kornienko and Tracy Caldwell Dyson, a shuttle veteran, will be welcomed aboard by Expedition 23 commander Oleg Kotov, Soichi Noguchi and NASA flight engineer Timothy Creamer.
The new arrivals will face a particularly busy first few days aboard the lab complex as the expanded Expedition 23 crew works to complete preparations for Discovery's arrival next week.
A few hours after the Soyuz docking Sunday, engineers at the Kennedy Space Center will roll a protective gantry away from Discovery, exposing the shuttle to view and setting the stage for the start of fueling at 8:56 p.m.
The shuttle astronauts - commander Alan Poindexter, pilot James Dutton, flight engineer Dorothy Metcalf-Lindenburger, Stephanie Wilson, Japanese astronaut Naoko Yamazaki and spacewalkers Richard Mastracchio and Clayton Anderson - plan to strap in around 3 a.m. Monday to await liftoff.
The goal of the 131st shuttle mission is to deliver 10 tons of supplies and equipment to the space station, including ammonia coolant, science racks, an experiment sample freezer and a crew sleep station.
The mission will be carried out in the deep overnight hours U.S. time. Assuming an on-time launch, the shuttle will dock with the space station around 3:44 a.m. Wednesday. Three spacewalks are planned, the first starting at 1:41 a.m. on April 9; the second at 2:16 a.m. on April 11; and the third at 3:11 a.m. on April 13.
If all goes well, Discovery will undock from the lab complex around 3:55 a.m. on April 16 and land back at the Kennedy Space Center two days later at 8:29 a.m.