Heaviest shuttle component

At lift off the space shuttle consists of the orbiter itself, the external fuel tank that feeds its main engines, and two solid rocket boosters attached to the tank that provide additional thrust. The most massive of all these four components at lift off is the tank, with a total mass of 760,000 kg (1,680,000 lb). There have been several versions of the external tank, including the ‘Super Lightweight Tank’, whose reduced mass provides increased performance of the space shuttle during launch.