Space Shuttle External Tank.

During the quarter hour of its operational life, the External Tank must provide the propellants and propellant conditioning for the Orbiter Main Engines, provide the structural support for the two Solid Rocket Boosters, withstand the natural and induced environments, and effect a safe disposal. The External Tank is twice the size of the S-II Stage used in the Saturn V Booster for the Apollo and Skylab Spacecrafts. The External Tank is 182 feet long, 27 feet in diameter, and carries 1,700,000 pounds of liquid oxygen and liquid hydrogen propellants. The Shuttle System configuration and the interaction of the system elements pose an intricate system sensitivity which must be analyzed to establish the performance and sizing requirements for the External Tank.