On August 12, 1977, NASA’s Space Shuttle Enterprise successfully made its first free flight test, as part of NASA’s Orbiter Approach and Landing Tests (ALT). The ALT program allowed shuttle pilots to explore the orbiter’s low-speed flight and landing characteristics.

Today’s (August 12) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.

Space Shuttle Enterprise

The concept of the Space Shuttle originated in the late 1960s. It was an attempt to reduce the cost of spaceflight by introducing a reusable spacecraft. In order to “reuse” the spacecraft, it should have the aerodynamic characteristics and in-atmosphere handling qualities of a conventional airplane. Back then the computers were not strong enough, and boosters were not reusable, so it was not an option to land boosters back as SpaceX does today.

In order to evaluate the orbiter’s flight control systems and subsonic handling characteristics, a series of flight tests were undertaken at NASA Dryden Flight Research Center in 1977.

Rolled out on September 17, 1976, a full-scale orbiter vehicle prototype, named Space Shuttle Enterprise and designated OV-101, was built for the Approach and Landing Tests (ALT).

On August 12, 1977, a modified Boeing 747 Shuttle Carrier Aircraft carried Space Shuttle Enterprise, a prototype orbiter, during eight captive tests to determine how well the two vehicles flew together and to test some of the orbiter’s systems. The free-flight phase of the ALT program allowed shuttle pilots to explore the orbiter’s low-speed flight and landing characteristics.

Space Shuttle Enterprise provided realistic, in-flight simulations of how subsequent space shuttles would be flown at the end of an orbital mission.

Space Shuttle Enterprise first free flight test (August 12, 1977)
August 12, 1977: The Space Shuttle Enterprise (a prototype) flies free of NASA’s 747 Shuttle Carrier Aircraft (SCA) during one of five free flights carried out at the Dryden Flight Research Facility, Edwards, California in 1977 as part of the Shuttle program’s Approach and Landing Tests (ALT). The tests were conducted to verify orbiter aerodynamics and handling characteristics in preparation for orbital flights with the Space Shuttle Columbia. A tail cone over the main engine area of Enterprise smoothed out turbulent airflow during flight. It was removed on the two last free flights to accurately check approach and landing characteristics.

The crewmembers of Space Shuttle Enterprise’s first free flight were Fred W. Haise, Jr. (commander) and C. Gordon Fullerton (pilot).

The flight began with orbiter separation from the Shuttle Carrier Aircraft (SCA) at an altitude of about 22,800 feet (6,950 meters) above ground level at 270 knots equivalent airspeed (KEAS). Haise and Fullerton executed two 90 percent left turns during descent and landed on lakebed runway 17 five minutes and 22 seconds after separation.

Space Shuttle Enterprise first free flight test (August 12, 1977) crew
The first crew of the Space Shuttle Approach and Landing Tests (ALT) in front of the prototype orbiter Enterprise at the Rockwell facility in Palmdale, California; commander Fred W. Haise, Jr. and pilot C. Gordon Fullerton.

The touchdown was approximately a mile beyond the predicted landing point. The crew performed steering, braking, and coasting tests during the 11,000-feet (3,350 meters) rollout.

Space Shuttle Enterprise performed a total of five free flights between August and October.

This first free flight, performed on August 12, 1977, saw Enterprise remain fitted with its aerodynamic tail cone, intended to reduce drag when mounted on the Shuttle Carrier Aircraft (SCA) during flight.

Performed on October 26, the fifth free flight, with the Enterprise landing on a concrete runway for the first time, revealed a problem with the space shuttle flight control system that made it susceptible to pilot-induced oscillation, a potentially dangerous control problem. Further research using various aircraft, particularly NASA Dryden’s F-8 Digital-Fly-By-Wire testbed, led to the correction of the problem before the first Orbital Test Flight of Space Shuttle Columbia.

Space Shuttle Enterprise – Free flight Test – ABC News (August 12, 1977)

August 12 in Science, Technology, Astronomy, and Space Exploration history

Sources

  • Space Shuttle Enterprise on Wikipedia
  • “Space Shuttle Enterprise rolls to the Pad” on the NASA website
  • Approach and Landing Tests on Wikipedia
  • PDF Document – “Free Enterprise: Contributions of the Approach and Landing Test (ALT) Program to the Development of the Space Shuttle Orbiter” on the NASA website
M. Özgür Nevres

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