Approach and Landing Tests

Infobox Space mission
mission_name = Approach and Landing Tests
insignia = ALT mission patch.png shuttle = Enterprise
crew_members = 2 x 2
launch_pad = N/A
launch = N/A
landing = N/A
duration = N/A
orbits = Not orbital flights
altitude = N/A
inclination = N/A
distance = N/A
crew_photo = ALT crew.png crew_caption = (L-R) Gordon Fullerton, Fred Haise, Joe Engle and Richard Truly pose in front of the prototype orbiter "Enterprise"
previous = ASTP
next = STS-1
The Approach and Landing Tests were a series of taxi and flight trials of the prototype space shuttle "Enterprise" to test the vehicle's flight characteristics both on its own and when mated to the Shuttle Carrier Aircraft, prior to the operational debut of the shuttle system.

Background

The Space Transportation System program originated in the late 1960s as a means of reducing the cost of spaceflight by introducing a reusable spacecraft. The final agreed design would feature a reusable spaceplane, disposable external tank and reuseable solid fuel boosters. The contract to build the spaceplane, which eventually came to be known as the "shuttle orbiter", was awarded to North American Aviation (later Rockwell International), with the first complete orbiter rolled out in 1976. Originally planned to be named "Constitution" (due to its completition being in the year of the United States Bicentennial), it was eventually decided that the prototype would bear the name "Enterprise".

Test program

Upon her entry into service, NASA began an extensive programme of tests using "Enterprise" to ensure all of the systems it had put in place for the shuttle project functioned as designed. These tests would encompass not only the flight tests planned to test the 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 programme, which had been christened by NASA as the "Approach and Landing Tests" (ALT).

Crew

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

Crew 1

Number in parentheses indicates number of spaceflights by each individual prior to this mission.
*Fred W. Haise, Jr (1) - Commander
*C. Gordon Fullerton - Pilot

Crew 2

*Joseph H. Engle - Commander
*Richard H. Truly - Pilot

huttle Carrier Aircraft

In addition to the two assigned shuttle crews, who would alternate crewing the orbiter, a single flight crew was attached to the Boeing 747 Shuttle Carrier Aircraft (SCA) for the entire program:
*SCA Crew:
**Fitzhugh L. Fulton, Jr (Captain)
**Thomas C. McMurty (Co-Pilot)
**Louis E. Guidry, Jr (Flight Engineer)
**Victor W. Horton (Flight Engineer)

ALT

The ALT programme was divided into three distinct phases. [ [http://spaceline.org/shuttlechron/shuttletest.html Space Shuttle Approach and Landing Tests Fact Sheet] From "Space Shuttle Chronology"; Accessed 11/03/08] The first phase was designated as the "taxi-test" phase, which involved the SCA and orbiter in a mated formation conducting taxi tests at Edwards to verify the taxiing characteristics of the aircraft while carrying the orbiter. These tests did not involve the orbiter in any way beyond it being mated to the aircraft, so consequently it remained powered down and uncrewed. A total of three taxi-tests were performed on February 15 1977. Following this, the programme moved into its next phase.

Captive flights

The captive flight phase of ALT saw the SCA/orbiter combination in flight as a test of the SCA's flying characteristics while mated to the orbiter, and as an initial test of the orbiter systems in flight. This was subdivided into two phases:

Captive - inert

There were a total of five captive-inert flights designed to test the flight and handling characteristics of the aircraft while it was mated to the orbiter. As with the taxi tests, this did not involve the orbiter beyond it being mated to the SCA, so it remained unpowered and uncrewed.

Captive - active

The captive-active flights were intended to determine the optimum profile required for "Enterprise" to separate from the SCA during the orbiter's free-flights. These were also intended to refine and test the orbiter crew procedures and to ensure the operational readiness of the orbiter's systems. For these three flights, although "Enterprise" remained mated to the SCA, it was powered and crewed.

Free-Flight

The final phase of flight testing involved the free-flights. This would see "Enterprise" mated to the SCA and carried to a launch height before being jettisoned by the use of explosive bolts to glide to a landing on the runways at Edwards. The intention of these flights was to test the flight characteristics of the orbiter itself, on a typical approach and landing profile from orbit. There were a total of five free-flights between August and October; the first three saw "Enterprise" remain fitted with its aerodynamic tail cone, intended to reduce drag when mounted on the SCA during flight. The final two had the tail cone removed, with the orbiter in its full up operational configuration, with dummy main engines and OMS pods. These five flights were to be the only time "Enterprise" flew alone.

Ferry flights

Following the free-flight tests, "Enterprise" was prepared for ferry flight tests, which were intended to ensure that the SCA/orbiter configuration was viable for flights of the duration between landing and launch sites. [ [http://www.astronautix.com/craft/entprise.htm Astronautix.com] Accessed 11/03/08]

After ALT

Following the end of the flight test programme, "Enterprise" was taken from Edwards AFB first to the Marshall Space Flight Center and then to the Kennedy Space Center for testing with the external tank and SRB in full-up launch configuration to test both the structural responses of the "stack" itself and the launch procedures prior to the entry into service and first launch of the first operational orbiter, "Columbia".

Table of ALT flights

Video Gallery

References