Discovery Gets "Go" for Launch

Discovery Gets "Go" for Launch

The mission management team has approved launch teams to continue with the countdown toward an 11:59 p.m. EDT liftoff to start space shuttle Discovery's STS-128 mission to the International Space Station. Filling of Discovery's external fuel tank with propellants began at 2:45 p.m. after an initial "no-go" due to weather in the area violating constraints.

The mission management team also reports that all the testing and analysis of Discovery's fill-and-drain valve during the last two days gives them a high degree of confidence the valve is working.

The shuttle team has approved procedures in case there is a similar issue with the position sensor on the hydrogen fill-and-drain valve.

The plan includes being able to open and close the valve, or cycle it, two times during the tanking process if the valve position indicator sensor doesn't work. Teams would use alternate means, including monitoring pressure in the system, to provide confidence the valve is closed for launch.
For launch time, forecasters are calling for a 60 percent chance of favorable weather.

The earliest the filling of Discovery's external fuel tank with 535,000 gallons of liquid hydrogen and liquid oxygen can begin is 2:34 p.m.