Most rockets either burn up in Earth’s atmosphere or are decommissioned after they have completed their mission. A new rocket has to be built from scratch for the next launch. All but one part of NASA’s Space Shuttle returns to Earth intact. After these parts have been checked for damage, they are ready to be used again, therefore saving the cost of rebuilding.
The U.S. space shuttle consisted of three major components: a winged orbiter that carried both crew and cargo; an external tank containing liquid hydrogen (fuel) and liquid oxygen (oxidizer) for the orbiter’s three main rocket engines; and a pair of large, solid-propellant, strap-on booster rockets. At liftoff the entire system weighed 2 million kilograms (4.4 million pounds) and stood 56 metres (184 feet) high. During launch the boosters and the orbiter’s main engines fired together, producing about 31,000 kilonewtons (7 million pounds) of thrust. The boosters were jettisoned about two minutes after liftoff and were returned to Earth by parachute for reuse. After attaining 99 percent of its orbital velocity, the orbiter had exhausted the propellants in the external tank. It released the tank, which disintegrated on reentering the atmosphere. Although the orbiter lifted off vertically like an expendable rocket launcher, it made an unpowered descent and landing similar to a glider.
The space shuttle could transport satellites and other craft in the orbiter’s cargo bay for deployment in space. It also could rendezvous with orbiting spacecraft to allow astronauts to service, resupply, or board them or to retrieve them for return to Earth. Moreover, the orbiter could serve as a space platform for conducting experiments and making observations of Earth and cosmic objects for as long as about two weeks. On some missions it carried a European-built pressurized facility called Spacelab, in which shuttle crew members conducted biological and physical research in weightless conditions.
The space shuttle launched like a rocket. But it landed like a glider airplane. The solid rocket boosters and the main engines on the orbiter helped the shuttle blast off from Earth like a rocket. The two boosters dropped off the shuttle two minutes after launch. They fell into the ocean. A special boat picked the boosters out of the ocean. They were used again for another flight. The external tank dropped off the orbiter after it had used all the fuel in the tank. The external tank would burn up over Earth. So the tank could not be used again.
When the shuttle orbiter returned to Earth, it came down from the sky like an airplane. Wheels came out from underneath the orbiter. It rolled to a stop on a runway. Then NASA would prepare it to fly on another mission.
Picture Credit : Google