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First Shuttle/747 Captive Flight First Shuttle/747 Captive Flight

Photo Number: ECN-6887
Photo Date: February 1977

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The Space Shuttle prototype Enterprise rides smoothly atop NASA's first Shuttle Carrier Aircraft (SCA), NASA 905, during the first of the shuttle program's Approach and Landing Tests (ALT) at the Dryden Flight Research Center, Edwards, California, in 1977. During the nearly one year-long series of tests, Enterprise was taken aloft on the SCA to study the aerodynamics of the mated vehicles and, in a series of five free flights, tested the glide and landing characteristics of the orbiter prototype.

In this photo, the main engine area on the aft end of Enterprise is covered with a tail cone to reduce aerodynamic drag that affects the horizontal tail of the SCA, on which tip fins have been installed to increase stability when the aircraft carries an orbiter.

The Space Shuttle Approach and Landings Tests (ALT) program allowed pilots and engineers to learn how the Space Shuttle and the modified Boeing 747 Shuttle Carrier Aircraft (SCA) handled during low-speed flight and landing. The Enterprise, a prototype of the Space Shuttles, and the SCA were flown to conduct the approach and landing tests at the NASA Dryden Flight Research Center, Edwards, California, from February to October 1977.

The first flight of the program consisted of the Space Shuttle Enterprise attached to the Shuttle Carrier Aircraft. These flights were to determine how well the two vehicles flew together. Five "captive-inactive" flights were flown during this first phase in which there was no crew in the Enterprise. The next series of captive flights was flown with a flight crew of two on board the prototype Space Shuttle. Only three such flights proved necessary. This led to the free-flight test series.

The free-flight phase of the ALT program allowed pilots and engineers to learn how the Space Shuttle handled in low-speed flight and landing attitudes. For these landings, the Enterprise was flown by a crew of two after it was released from the top of the SCA. The vehicle was released at altitudes ranging from 19,000 to 26,000 feet.

The Enterprise had no propulsion system, but its first four glides to the Rogers Dry Lake runway provided realistic, in-flight simulations of how subsequent Space Shuttles would be flown at the end of an orbital mission. The fifth approach and landing test, with the Enterprise landing on the Edwards Air Force Base concrete runway, revealed a problem with the Space Shuttle flight control system that made it susceptible to Pilot-Induced Oscillation (PIO), a potentially dangerous control problem during a landing. Further research using other NASA aircraft, especially the F-8 Digital-Fly-By-Wire aircraft, led to correction of the PIO problem before the first orbital flight.

The Enterprise’s last free-flight was October 26, 1977, after which it was ferried to other NASA centers for ground-based flight simulations that tested Space Shuttle systems and structure.

NASA Photo by: NASA

Keywords: Enterprise; Approach and Landing Tests (ALT); Dryden Flight Research Center; Shuttle Carrier Aircraft (SCA); Boeing 747; PIO; Edwards Air Force Base; Shuttle Carrier Aircraft (SCA); Boeing 747; PIO; Edwards Air Force Base

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