Space Shuttle Discovery is ready for launch of mission STS-116 from Launch Pad 39B. The rotating service structure rolled back at approximately 9:30 a.m. this morning to enable launch.
NASA officials have set the next launch attempt for tonight at 8:47 p.m. EST. According to the 45th Weather Squadron, there is a 70 percent chance of weather prohibiting launch due to concerns with crosswinds and a slight chance for rain showers. Weather is acceptable at the three transatlantic abort landing sites, located in Spain and France.
The forecast for Sunday and Monday calls for a 60 percent chance of weather prohibiting launch. For Tuesday and Wednesday, the forecast improves a bit, indicating a 40 percent chance of unfavorable weather due to cloud cover, crosswinds and the potential for showers.
Discovery’s orange external tank is being filled with 500,000 gallons of liquid oxygen and hydrogen. This process, called “tanking,” takes about three hours to complete. The propellant levels in the tank will be continuously “topped off” during the remainder of today’s countdown. Today’s tanking began at 12:46 p.m. with the chilldown of the propellant lines, followed by the start of the filling process at 12:53 p.m.
The STS-116 mission is the 33rd for Discovery and the 117th space shuttle flight. During the 12-day mission, the crew will continue construction on the International Space Station, rewiring the orbiting laboratory and adding a segment to its integrated truss structure.