The main components of the Space Transport system (Space Shuttle) are the Orbiter Vehicle (OV), a pair of recoverable Solid Rocket Boosters (SRBs), and the expendable External Tank (ET) containing liquid hydrogen and liquid oxygen to fuel the shuttle's main engines.

The Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines.

The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion.

Two Solid Rocket Boosters (SRBs) operate in parallel with the space shuttle main engines for the first two minutes of flight after launch.

This provides the additional thrust needed for the orbiter to escape the gravitational pull of the Earth. The boosters also assist in guiding the entire vehicle during this initial ascent.

At an altitude of approximately 45 km (24 nautical miles), the boosters fuel is used up and they are separated from the orbiter/external tank. The boosters then descend on parachutes into the Atlantic Ocean to be recovered by ships, returned to land and refurbished for reuse.

The SRB motor is the largest solid propellant motor ever developed for space flight and the first built to be used on a piloted craft.

The propellant used in the motor is powdered aluminum mixed with oxygen provided by a chemical called ammonium perchlorate.

It is mixed in 600 gallon bowls located in three different mixer buildings at a plant in Utah. It is then taken to special casting buildings and poured into the casting segments. Cured propellant looks and feels like a hard rubber eraser.