The External Tank that will help launch Space Shuttle Discovery on its Return to Flight mission is expected to roll out Thursday afternoon, Dec. 30, from NASA's Michoud Assembly Facility near New Orleans to begin its journey to NASA's Kennedy Space Center, Fla., where it will be prepared for launch. The tank is scheduled to leave New Orleans on its barge Friday morning Dec. 31.

The tank, known as ET-120, will roll out on its transporter from the final assembly building and be loaded onto a covered barge docked at the Michoud Facility. The barge is expected to take four to five days to travel from the Mississippi River-Gulf of Mexico Outlet to Florida's Banana River, which pours into the Atlantic Ocean.

The gigantic, rust-colored external tank is the largest element of the Space Shuttle system at 27.6-feet wide and 154-feet tall. During the first eight-and-a-half minutes of launch, the tank feeds 535,000 gallons of liquid hydrogen and oxygen to the Shuttle's three main engines, powering the Shuttle to space during ascent. The tank is the only Shuttle component not reused. It withstands more than 7 million pounds of thrust during liftoff and ascent.

ET-120 is the first to incorporate safety improvements to address the Columbia Accident Investigation Board's recommendation to reduce the risk to the Shuttle from falling debris during ascent. Investigators believe that during Columbia's launch in January 2003, insulating foam from the bipod area fell off the External Tank and damaged the left wing of the Orbiter.

The Space Shuttle Propulsion Office at NASA's Marshall Space Flight Center in Huntsville, Ala., manages the tank project. Lockheed Martin Space Systems Co. is the primary contractor for the tank.

FMI: www.nasa.gov/returntoflight