Sunday, August 23, 2009

Live At KSC: Forecast For Fuel-Loading Worsens

Discovery's power-producing fuel cells have been serviced and NASA is continuing to march through the countdown to a planned launch early Tuesday of one on only seven more shuttle missions on agency books.

Discovery and seven astronauts remain scheduled to launch from Kennedy Space Center at 1:36 a.m. Tuesday on a mission to haul tons of supplies and equipment to the International Space Station -- gear considered crucial to keeping a full staff of six people working on the outpost.

The weather forecast for launch improved. Meteorologists say there is an 80 percent chance conditions will be acceptable for launch during a 10-minute window that will open at 1:31 a.m. Tuesday. NASA targets the middle of the window to get the most propulsive power on the nine-minute climb into orbit.

The forecast for tanking, however, got worse. Meteorologists say there is a 40 percent chance that central Florida thunderstorms will produce lightning within five nautical miles of the launch pad around 4 p.m. Monday.

That's when NASA is scheduled to begin loading a half-million gallons of supercold liquid hydrogen and liquid oxygen into the shuttle's external tank. Lightning within five miles would force NASA to delay propellant-loading operations. Tanking would need to get under way by about 6 p.m. or so in order to make a launch attempt early Tuesday.

Check out the details in this Official Forecast from the Air Force 45th Space Wing Weather Squadron.

The wing provides tracking, range safety and weather forecasting services for all launches from KSC or nearby Cape Canaveral Air Force Station.

Engineers in Firing Room 4 of the Launch Control Center completed the loading of liquid hydrogen and liquid oxygen into storage tanks beneath the liner of the shuttle's payload bay.

The chemical reactants are combined in the shuttle's three fuel cells to generate electricity to run all spaceship systems in flight. A full load is critical to providing enough electricity to complete any given shuttle mission.

Discovery's flight is expected to last 13 days, but there is enough liquid hydrogen and liquid oxygen on board now to extend the mission three days if required.

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