NASA - National Aeronautics and Space Administration

Space shuttle external tank, ET-128, rolls into the Vehicle Assembly building at Kennedy Space Center, Fla., March 26. Image Credit: NASA/KSC
Marshall is the world's leader for meeting America's space propulsion challenges and putting new rockets and explorers into space, acquiring this position of leadership through the Mercury, Gemini, Apollo and space shuttle programs, and now with the next generation of Ares rockets.

Marshall is responsible for the space shuttle’s propulsion system, consisting of the main engines, the solid rocket boosters with their solid rocket motors, and the external tanks. The three high-performing, reusable liquid propellant rocket engines, along with the solid rocket boosters, provide more than 7.8 million pounds of thrust to lift the space shuttle to orbit.

Space Shuttle Reusable Solid Rocket Boosters

Located on both sides of the orange external tanks, the solid rocket boosters are the pair of large solid rockets used by the space shuttle during the first two minutes of powered flight, providing the thrust needed for the orbiter to escape Earth’s gravity. The solid rocket boosters consist of the entire rocket assembly, which include the reusable solid rocket motors, recovery parachutes, electronic instrumentation, separation rockets, range safety destruct system, and thrust vector control.

Assisting with the guidance of the entire vehicle during initial ascent, the boosters operate in parallel with the three main engines and provide about 85 percent--6.6 million pounds--of the main thrust to propel the Space Shuttle off the launch pad and up to an altitude of about 150,000 feet—about 30 miles. After their two minutes of flight, the boosters separate from the external tank, descend under parachutes and land in the Atlantic Ocean. The used solid rocket boosters are recovered by ships, refurbished, reloaded with propellant, and reused for the future missions.

Space Shuttle Main Engines

The three space shuttle main engines mounted in the back of the orbiter along with the twin solid rocket boosters, provide the thrust to lift the orbiter off the ground for the initial shuttle ascent.

Ignited just before shuttle liftoff, the main engines operate for 8.5 minutes, the duration of the shuttle's powered flight. Each engine produces more than 375,000 pounds of thrust, four times that of the largest engine flown on commercial jets. Combined, the engines provide more than 1.2 million pounds of thrust, enough to accelerate the shuttle to more than 17,500 mph to reach Earth orbit. As the shuttle accelerates, the main engines burn a half-million gallons of liquid propellant supplied by the external fuel tank. The space shuttle main engines are reused for multiple flights.

The Marshall Center is responsible for design, development, manufacturing, assembly, testing and flight performance of the main engines.

Space Shuttle External Tank

The external tank holds the propellant -- hydrogen and oxygen -- used by the space shuttle main engines for launch of the space shuttle. It is the structural backbone for the shuttle, supporting the vehicle on the launch pad and absorbing the 7.3 million pounds of thrust generated during launch. The largest single piece of the space shuttle, the tank is154 feet tall which is more than half the length of a football field. After the fuel is consumed at approximately 8.5 minutes into a space shuttle flight, the external tank is jettisoned from the orbiter. The tank is machined from aluminum alloys and its skin is less than a half-inch thick. The space shuttle’s external tank is not reused.

The external tanks are manufactured by Lockheed Martin at NASA’s Michoud Assembly Facility in New Orleans, La.