Sixteen minutes after the liftoff of STS-29, the Space Shuttle Discovery's jettisoned External Tank (ET) is seen here, in a photograph by shuttle astronaut James P. Bagian, falling back towards Earth. The 154 foot long ET is the largest non-reusable component in the Shuttle system. After carrying over 500,000 gallons of liquid propellant to feed the shuttle's main engines during liftoff, its ultimate fate is to re-enter the atmosphere, break up and descend into a remote ocean area. The side of this ET shows a normal burn scar caused during the separation of one of the reusable solid rocket boosters.