SPACESHUTTLE

THE SPACE SHUTTLE

In the early 1980s, the Space Transportation System (STS), better known as the space shuttle, became the major U.S. space program. The shuttle, a multipurpose, orbital-launch space plane, was designed to carry payloads of up to about 30,000 kg (65,000 lb) and up to seven crew members and passengers. The upper part of the spacecraft, the orbiter stage, had a theoretical lifetime of perhaps 100 missions, and the winged orbiter could make unpowered landings on returning to earth. Because of the shuttle’s designed flexibility and its planned use for satellite deployment and the rescue and repair of previously orbited satellites, its proponents saw it as a major advance in the practical exploitation of space. Others, however, worried that NASA was placing too much reliance on the shuttle, to the detriment of automated vehicles and missions.

Problems with the shuttle eventually led to resumption of the use of expendable launch vehicles (ELVs) for launching satellites. The U.S. had planned to replace the space shuttle with a new spacecraft, the X-30, in the 1990s. Faced with budgetary constraints, however, the U.S. decided to rely instead on a mixed fleet of ELVs and space shuttles to place payloads into orbit for the remainder of the decade. In July 1996, NASA gave the go-ahead for construction of the X-33, a one-half scale model of a new reusable launch vehicle (RLV). The X-33 was expected to be ready for flight testing by 1999.

Flight Testing Programs and Early Shuttle Missions.

In the late 1970s and early 1980s, two types of flight testing programs were organized: the approach and landing test (ALT) program and the orbital flight test program. During the ALT program (February–November 1977) the first space shuttle orbiter, a test vehicle called Enterprise, demonstrated that it could fly in the atmosphere and land like an airplane. Because it was not equipped for space travel, the Enterprise was launched from atop an airborne 747 aircraft.

The orbital flight test program began on April 12, 1981, with the launch into orbit of the space shuttle Columbia from the Kennedy Space Center in Florida; considered the first true spaceship, Columbia maneuvered through space during its 36 orbits and landed on a runway at Edwards Air Force Base in California two days later. The shuttle program’s first operational mission took place on Nov. 11, 1982, when Columbia deployed two commercial communications satellites. Over the next decade, Columbia was joined in the shuttle fleet by Challenger in 1982 (see below), Discovery in 1983, Atlantis in 1985, and Endeavour in 1991.

Early memorable flights included mission STS-7, on June 18–24, 1983, whose crew included the first U.S. woman astronaut, Sally K. Ride; mission STS-9, on Nov. 28–Dec. 8, 1983, which carried the first of the European Space Agency’s Spacelabs; mission 41-C, on April 6–13, 1984, during which a satellite was retrieved, repaired, and redeployed; and mission 51-A, on Nov. 8–16, 1984, when two expensive malfunctioning satellites were retrieved and returned to earth. By mid-decade, the shuttle launch program was behind schedule. Increasingly the shuttle was being used for U.S. military missions, and it faced stiff competition from the European Space Agency’s automated Ariane program for the orbiting of satellites.

Challenger Disaster.

On Jan. 28, 1986, the shuttle Challenger was destroyed about one minute after launch because of the failure of an O-ring, a sealant ring, on one of its solid rocket boosters. The booster nosed into the main propellant tank of liquid hydrogen and oxygen, causing a near-explosive disruption of the entire system. Seven astronauts were killed in the disaster: commander Francis (Dick) R. Scobee (1939–86); pilot Michael J. Smith (1945–86); mission specialists Judith A. Resnik (1949–86), Ellison S. Onizuka (1946–86), and Ronald E. McNair (1950–86); and payload specialists Gregory B. Jarvis (1944–86) and Christa McAuliffe (1948–86). McAuliffe had been selected the preceding year as the first “teacher in space,” a civilian spokesperson for the shuttle program.

The tragedy brought an immediate halt to shuttle flights until systems could be analyzed and redesigned. A presidential commission headed by former secretary of state William Rogers and former astronaut Neil Armstrong placed much of the blame on NASA’s administrative system and its failure to maintain an effective system of quality control.

The Shuttle after Challenger.

In the aftermath of the Challenger disaster, the O-ring seals on the solid rocket booster were redesigned, a replacement shuttle was ordered, and NASA's goal of flying two dozen shuttle missions a year was scaled back. The shuttle launch program resumed on Sept. 29, 1988, with the flight of Discovery and its crew of five astronauts. On this mission (STS-26) a NASA communications satellite, TDRS-3, was placed in orbit and a variety of experiments were carried out. The success of this mission encouraged the U.S. to resume an active launch schedule. By the end of 1997 another 62 shuttle missions had been flown, including the deployment in 1990 of the $1.5 billion Hubble Space Telescope, a daring mission to repair the malfunctioning telescope in 1993, and a servicing mission for the telescope in 1997. Notable in 1998 were the last two scheduled shuttle missions to Mir, John Glenn's highly publicized return to space aboard Discovery , and the deployment of the first two pieces of the International Space Station.

Columbia Disaster.

After a series of successful missions in the late 1990s and early 2000s, mostly to support the construction and servicing of the International Space Station, the U.S. space program experienced its worst disaster since the loss of the Challenger . On Feb. 1, 2003, at the end of a 16-day scientific research mission, the space shuttle Columbia disintegrated while reentering the earth's atmosphere, 16 min before its scheduled landing; the fiery explosion left a huge trail of debris, mostly in E Texas. All seven astronauts on board the Columbia were killed: commander Rick Husband (1957-2003); pilot William (Willie) McCool (1961-2003); mission specialists Michael Anderson (1959-2003), David Brown (1956-2003), Kalpana Chawla (1961-2003), and Laurel Clark (1961-2003); and payload specialist Ilan Ramon (1954-2003), the first Israeli astronaut to fly in space. The flight was Columbia 's 28th mission and the 113th mission of the shuttle program overall. Preliminary analysis determined that the spacecraft broke apart after superheated gases, or plasma, breached the shuttle's skin and penetrated the left wheel well. All other shuttle flights were suspended until investigators could determine what had caused the breach and what other factors, if any, might have contributed to the disaster.