Space Shuttle External Tank - Overview

Overview

The ET is the largest element of the space shuttle, and when loaded, it is also the heaviest. It consists of three major components:

• the forward liquid oxygen (LOX) tank
• an unpressurized intertank that contains most of the electrical components
• the aft liquid hydrogen (LH₂) tank; this is the largest part, but it is relatively light, due to hydrogen's very low density.

The ET is the "backbone" of the shuttle during launch, providing structural support for attachment with the solid rocket boosters (SRBs) and orbiter. The tank is connected to each SRB at one forward attachment point (using a crossbeam through the intertank) and one aft bracket, and it is connected to the orbiter at one forward attachment bipod and two aft bipods. In the aft attachment area, there are also umbilicals that carry fluids, gases, electrical signals and electrical power between the tank and the orbiter. Electrical signals and controls between the orbiter and the two solid rocket boosters also are routed through those umbilicals.