September 2007

Volume 1, Issue 1

Clear Brook High School

Engineering, Agriculture, Technology

Innovation History : Space Shuttle

During the 1960s, the U.S. National Aeronautics and Space Administration (NASA) launched large numbers of expendable space vehicles. By the early 1970s it seemed like a good idea to replace these expensive rockets with a reusable space booster. After a study of several designs, NASA in 1972 decided to construct a Space Transportation System (STS) based on the space shuttle. The shuttle takes off vertically, orbits Earth a number of times, and returns as a glider, supported by stubby wings. A huge external fuel tank is jettisoned after takeoff and burns up when reentering the atmosphere, but two solid-state booster rockets descend on parachutes and are reusable. Comparable in size to a DC-9 aircraft, the space shuttle carries payloads of up to 29,500 kg (65,000 lb) in its huge 18.3-m (60-ft) long cargo bay. A 15.25-m (50-ft) mechanical arm is used to manipulate the payload. With this arm, astronauts lift satellites out of the cargo bay and place them into near-Earth orbit. A total of five space shuttles were built. The first,              Columbia, began with a two-  day mission, making a perfect                  landing in 1981. This flight         marked the start of a series of                  scientific and military shuttle                  missions. Shuttle crews                  placed many satellites in or                 bit, conducted experiments,                  and retrieved several satel                 lites for repair. Flights were

temporarily halted after Challenger exploded shortly after takeoff in 1986, killing the crew of seven people. Although shuttle flights resumed on September 29, 1988, it was apparent that the use of shuttles with human crews was an expensive and dangerous way to place satellites in orbit. NASA once again turned to expendable rockets for routine launches, but still used shuttle flights for some satellite launches as well as for other purposes, including construction work on the International Space Station. But on February 1, 2003, another shuttle and its crew were lost. Columbia broke up during reentry, killing its crew of seven and once again halting the shuttle program. The shuttle has made possible many feats in space that only humans can do, such as capturing and correcting defects in existing satellites. The Russian alternative –– a Russian shuttle flew only a single test flight with no crew aboard –– has been to launch humans using giant expendable rockets and then parachute them back to Earth. Russia has lost fewer cosmonauts using this approach than the 14 lost in shuttle disasters, but that approach too has had its share of problems, including once when the parachute failed to open. NASA has explored alternatives to the shuttle, including fully reusable craft that could land at ordinary airplane speeds, but none of these were close to deployment at the time of the Columbia disaster.

Source : Bunch, Bryan. The History of Science and Technology. “““(HOUGHTON MIFFLIN COMPANY