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January 15, 1999 - 11th Grade


The three main parts of the United States Space Shuttle are a reusable winged orbiter, two reusable solid-rocket boosters, and a non-reusable liquid external fuel tank.

The orbiter consists of three parts: the crew cabin, cargo bay, and main engines. The crew occupies a two-level cabin at the forward end. They operate the vehicle from the upper level, the flight deck.

The cargo bay carries large and heavy payloads into Earth orbit, such as satellites. The cargo bay also houses the Remote Manipulator System also called the shuttle ³arm², which is a 50 foot long arm that is remotely controlled from the flight deck of the orbiter. The arm is used to hold payloads for deployment out of the payload bay or retrieving and securing for return to Earth.

The three main engines are mounted on the orbiter aft fuselage in a triangular configuration. The engines are spaced so that they are movable during flight to steer the Shuttle as well as provide thrust for launch in conjunction with the two solid rocket boosters. Fuel for the main engines is liquid hydrogen and liquid oxygen which is contained in the external tank.

The two solid rocket boosters are each 149.1 feet high and 12.2 feet in diameter. Each weighs 1,300,000 pounds. They are made of four-factory prepared segments filled with propellant at the manufacturerıs facility and assembled at the launch site. The segmented design permits ease of fabrication, transportation, and handling. Their solid propellant consists of a mixture of Aluminum powder, Ammonium Perchlorate powder, and Iron Oxide catalyst, held together with a polymer binder.

The exhaust nozzle in the aft segment of each motor can be moved up to eight degrees by the booster thrust control system which is controlled by the orbiter guidance and control computer.

At burnout the two solid rocket boosters are separated from the external tank by pyrotechnic devices and moved away from the Shuttle by eight separation motors. The recovery system, in the forward section of the booster, consists of parachutes and a homing device. After recovery, the boosters are disassembled and refurbished.

The Space Shuttled external fuel tank is the largest single element and the only major non-reusable component of the Shuttle system. It is three components in one: a liquid oxygen tank located in the forward position; a liquid hydrogen tank located aft; and an intertank assembly that connects the two propellant tanks and houses the forward solid rocket booster attachment points.

The external tank is 154 feet long and 27.6 feet in diameter and weighs approximately 1,655,600 pounds and carries more than 528,600 gallons of cryogenic propellants that are fed to the orbiterıs three main engines during powered flight. The external fuel tank falls toward Earth following itıs jettison and burns up in the atmosphere.