Approach and Landing Tests

The Approach and Landing Tests were a series of sixteen taxi and flight trials of the prototype Space Shuttle Enterprise that took place between February and October 1977 to test the vehicle's flight characteristics. Of the sixteen taxi-tests and flights, eleven saw Enterprise remain mated to the Shuttle Carrier Aircraft (SCA), while the final five had the shuttle separate from the SCA, with the on-board crew flying and landing the spacecraft.

The Space Shuttle program originated in the late 1960s as an attempt to reduce the cost of spaceflight by introducing a reusable spacecraft. The final agreed design would feature a reusable spaceplane, a disposable external tank and reusable solid-fuel rocket boosters. The contract to build the spaceplane, which eventually came to be known as the "orbiter", was awarded to North American Rockwell (later Rockwell International), with the first complete orbiter rolled out in 1976. Originally planned to be named Constitution (due to its completion being in the year of the United States Bicentennial), a letter-writing campaign by Star Trek fans persuaded President Gerald Ford to change the name of the prototype to Enterprise. It was unveiled to the public on September 17, 1976, with several members of the Star Trek cast in attendance.

Upon the orbiter's entry into service, NASA began an extensive program of tests using Enterprise to ensure all of the systems it had put in place for the Shuttle program functioned as designed. These tests would encompass not only the flight tests planned to test the flight characteristics of the orbiter, but also ground-based testing of the launch pad systems and procedures. In January 1977, Enterprise was taken by road from the Rockwell plant at Palmdale, California, to the Dryden Flight Research Center at Edwards Air Force Base to begin the flight test phase of the program, which had been christened by NASA as the Approach and Landing Tests (ALT).

The program lasted from February until October 1977, with a pair of two-man crews assigned to the orbiter:

Haise had previously flown as the Lunar Module pilot of Apollo 13, and was named as the commander of the original STS-2 mission. Fullerton later flew as the pilot of STS-3 and commanded STS-51-F.

This crew later flew on STS-2. Engle was originally a USAF pilot on the X-15, and had already gained Astronaut wings by the time he joined NASA. He flew his second Shuttle mission on STS-51-I. Truly flew his second Shuttle mission as commander of STS-8.

In addition to the two assigned Shuttle crews, who would alternate crewing the orbiter, a flight crew was attached to the Boeing 747 Shuttle Carrier Aircraft (SCA) for the entire program. This consisted of a captain and first officer, plus a pair of flight engineers:

The ALT program was divided into three phases.