The External Tank contains the liquid hydrogen (LH2) fuel and liquid oxygen (LO2)
oxidizer and supplies them under pressure to the three main engines in the orbiter during liftoff and ascent. The
ET can hold 383,000 gallons of LH2 and 143,000 gallons of LO2. Together, they
weigh a little more than 790 tons.
The external tank is 154.2 feet long and has a diameter of 27.5 feet. It is made of a welded aluminum alloy cylinder
with an ogive nose and a hemispherical tail.
When the main engines are shut down the external tank is jettisoned, enters the earth’s atmosphere, breaks up,
and impacts in a remote ocean area. It is not recovered.
Thanks to United Space Alliance for the images.