The first Space Shuttle, Enterprise, is a test vehicle designed to operate in the atmosphere; it is not equipped for spaceflight. Enterprise was rolled out at Rockwell International's assembly facility in Palmdale, California in 1976. In 1977, it entered service at NASA's Dryden Flight Research Center, Edwards Air Force Base, for a nine-month-long approach and landing test program. The vehicle was flown atop the Boeing 747 Shuttle carrier aircraft and also released for piloted free-flights and landings to check out all systems and performance characteristics. This test program was a necessary prelude to the first orbital flight by the Space Shuttle Columbia in 1981.

The Space Shuttle made its debut in 1981 as the new U.S. launch vehicle for human spaceflight in Earth orbit. It was developed for a variety of purposes: satellite delivery and retrieval, orbital servicing, roundtrip service for science instruments, and laboratory research in space. Intended to be an economical replacement for expendable launch vehicles that are used only once, it was the world's first re-flyable spacecraft.

In the post-Apollo era, the Space Shuttle was intended to make access to space "routine" and less expensive. To meet these goals, it had to be reusable and economical to develop and operate. Thus, the design of the Shuttle was shaped not only by engineering considerations but also by interests of the White House, Congress, and Department of Defense. The military, commercial, and scientific communities have used the Shuttle for their projects in space.

The Space Shuttle is the centerpiece of the U.S. Space Transportation System. The vehicle consists of an orbiter, an external propellant tank, and two solid rocket boosters. Only the orbiter goes into space. Designed to operate on land, in the atmosphere, and in space, the orbiter combines features of a rocket, an aircraft, and a glider. No other flying machine is launched, serves as a crew habitat and cargo carrier, maneuvers about in orbit, then returns from space for an unpowered landing on a runway, and is ready to do it all again in a few weeks.

The main role of the test vehicle Enterprise (OV-101, for Orbital Vehicle 101) was to check the Shuttle's flight characteristics and performance. NASA conducted the approach and landing test program from February through November 1977 at the Dryden Flight Center. Ground tests included taxi tests with Enterprise mounted atop the Boeing 747 Shuttle carrier aircraft to determine loads, control characteristics, steering, and braking of the mated vehicles. Five captive flights of Enterprise attached to the 747 were conducted, with the Shuttle unmanned and its systems inert, to assess structural integrity and performance of the mated craft in flight. Three manned captive flights followed, with an astronaut crew aboard the Shuttle (still attached to the 747 aircraft) operating and evaluating its activated systems in flight. Finally, two astronaut crews took turns piloting the 150,000-lb. Shuttle test vehicle to five free-flight landings at Edwards Air Force Base under conditions simulating a return from space.

Upon completion of the approach and landing tests, Enterprise was used for vibration tests at Marshall Space Flight Center in Alabama and for launch complex fit checks at Kennedy Space Center in Florida and Vandenberg Air Force Base in California. In 1983, it appeared in the Paris Air Show and other sites in Europe, and was a featured attraction at the 1984 World's Fair in New Orleans. In 1985, NASA transferred Enterprise to the Smithsonian Institution's National Air and Space Museum where it remained in a storage hangar at Washington's Dulles International Airport. In November, 2003, Enterprise was moved to the nearby Steven F. Udvar-Hazy Center where it is now on public display.