GN17986C.jpg: Picture shows the orbiter Discovery being positioned for remating to the new External Tank 121, and Solid Rocket Boosters. ET-121, was originally slated to fly with Atlantis on mission STS-121, but will now help carry Discovery into space on the upcoming STS-114 mission. The tank has a new heater for the liquid oxygen feedline bellows area, to eliminate ice buildup which could lead to debris hitting the orbiter. Must credit NASA/KSC