External Fuel Tank
Backdropped by the blue and white of Earth, the STS-125 external fuel tank (ET) begins its relative separation from the Space Shuttle Atlantis following launch. The external fuel tank contains the liquid hydrogen fuel and liquid oxygen oxidizer Used by the space shuttle orbiter during launch. It was jettisoned just over 10 seconds after MECO (Main Engine Cut Off), where the SSMEs were shut down. It then burned up as it re-entered the Earth's atmosphere. Unlike the Solid Rocket Boosters, external tanks were not re-used. They broke up before impact in the Ocean.
NASA / JPL Image