To Boldly Go Where No Man Has Gone Before: Space Shuttle Enterprise

Space Shuttle Enterprise (OV-101) was the first orbiter of the Space Transportation System, or Space Shuttle Program. She was constructed as an orbital test vehicle with the intent of not flying in space but rather remaining on Earth for ground and aerial tests. These aerial tests were known as Approach and Landing Tests (ALT) and were flown by four NASA astronauts, three of which would command later Space Shuttle missions. The vehicle itself was significant because it was the first spacecraft designed with the "aerodynamic characteristics and in-atmosphere handling qualities of a conventional plane" (NASA).

Enterprise during an approach and landing test (NASA)

The abridged story of Space Shuttle Enterprise begins on January 5, 1972 when President Richard Nixon announced his approval of the Space Transportation System and subsequent construction of reusable vehicles for flight, stating it would "revolutionize transportation into near space." NASA awarded North American Rockwell of Downey, California, the contract to build the vehicle known as an orbiter. Manufacturing of the very first components began in June 1974.

Enterprise's original name was Constitution after the Constitution of the United States and was scheduled to be unveiled on Constitution Day. However, fans of the science fiction television series Star Trek advocated for the name change Enterprise after the spaceship featured in the show. They wrote to the White House asking the president at the time, Gerald Ford, to convince NASA to modify the orbiter's name. While he did not mention this campaign to NASA, he did order the agency to change the name of the new spaceship, saying he was "partial to the name". Enterprise made its first public rollout at Rockwell's Palmdale, California facility on September 17, 1976. Several Star Trek cast members as well as the series creator, Gene Roddenberry, NASA Administrator James Fletcher, and the astronauts scheduled to fly her were in attendance.

NASA Administrator James Fletcher with DeForest Kelley, George Takei, James Doohan, Nichelle Nichols, Leonary Nimoy, creator Gene Roddenberry, unnamed NASA official, and Walter Koenig

(NASA)

In January the following year, Enterprise was sent to NASA's Dryden Flight Research Center (now Armstrong Flight Research Center) at Edwards Air Force Base, California. The orbiter was placed on the back of the Shuttle Carrier Aircraft (SCA), a modified Boeing 747, for aerial tests. These tests would demonstrate the orbiter's capability for safe approach and landing after returning from space, as well as validate critical onboard control systems. Both of these goals were crucial for flying crewed operational Shuttle missions. Four astronauts piloted the Approach and Landing Tests: Fred Haise, the only non-rookie, was the lunar module pilot (LMP) of the ill-fated Apollo 13 mission in 1970 and the backup commander for Apollo 16 in 1972 [1]. Gordon Fullerton, his pilot for ALT, was a former Manned Orbiting Laboratory astronaut and part of NASA's seventh class. Joe Engle was the backup LMP of Apollo 14 in 1971 and the original LMP of Apollo 17 set to fly in 1972, but was replaced by geologist Jack Schmitt. Dick Truly was another former Manned Orbiting Laboratory astronaut who transferred to NASA with Fullerton when the program was terminated in 1969. The crew members for the SCA were pilots Fitzhugh Fulton and Thomas McMurty and flight engineers Vincent Alvarez, Thomas Guidry, Victor Horton, and William Young.

Fullerton, Haise, Engle, and Truly post with Enterprise (NASA)

During 1977, a series of both captive and active flights took place at Edwards. Enterprise had no thermal protection unlike future orbiters because the craft stayed in Earth's atmosphere. Instead, other materials were used to simulate the actual weight of a flight-worthy orbiter. The flight deck also only held two astronauts, a commander and a pilot. Additionally, for three of its free flights a fairing covered the aft end while dummy main engines were installed for the final two flights. This was to "simulate weight and aerodynamic characteristics of an operational orbiter" (NASA).

Five captive, inert flights of Enterprise verified the airworthiness of the SCA as a transport vehicle. Afterwards, the orbiter was powered up and the crew tested cockpit controls during three captive-active flights. The final phase consisted of five free flights with release from the 747 and gliding and landing at Edwards. The first four flights landed on the dry lake beds of Rogers Dry Lake. The final flight, on the other hand, ended on the concrete runway of the base and demonstrated the precision landing capabilities of the orbiter needed for later missions. At touchdown, however, the orbiter experienced a pilot-induced oscillation. This is when the vehicle skips and bounces down the runway several times.

One of Enterprise's first three approach and landing tests (NASA)

In March of 1978, Enterprise was flown to Marshall Space Flight Center in Huntsville, Alabama and mated with the external fuel tank (ET) and solid rocket boosters (SRBs) for the first time. The complete ship, known as the "stack", was installed in the Dynamic Structural Test Facility and put through a series of vibration tests. These tests simulated conditions expected during launch. After a year at Marshall she was flown to the Kennedy Space Center in Florida on the back of the SCA and put on display at the Shuttle Landing Facility for five days, attracting an estimated 75,000 visitors. While in Florida, Enterprise was used to validate final procedures before launch.

The orbiter was moved inside the Vehicle Assembly Building (VAB) and again mated to the ET and SRBs, this time on a Mobile Launcher Platform (MLP). The MLP is what a rocket or launch vehicle sits on while inside an integration facility and on its way to the launch pad. While in the VAB, tests of Enterprise verified towing, assembly, and checkout procedures. Afterwards the stack was rolled out to Launch Complex 39-A. This lengthy and sometimes grueling process was performed at varying speeds to find the most favorable speed to minimize vibration stress on the vehicle. Once on the launch pad, the Shuttle was used to conduct fit checks and validate launch procedures, the most critical step of which was the countdown demonstration test. During this time the ET is filled with liquid hydrogen and liquid oxygen. It was found that ice accumulated at the top of the tank during fueling, which had dangerous consequences. To prevent this, engineers added what is known as the "beanie cap", a gaseous oxygen vent hood, to shroud the very top of the ET.

Enterprise sitting on LC-39A (NASA)

By August 1979 Enterprise was finished at the Kennedy Space Center and flew back to Dryden. It made stops along the way and was visited by an estimated 750,000 people during her seven day trip. The orbiter returned to Palmdale in October and was stripped of her onboard computers and instruments, which were refurbished and installed into the new ships still under construction. Enterprise went back to Edwards in September 1981 for long-term storage— by then Space Shuttle Columbia was flying. For the next few years the shuttle toured the United States and western Europe, including France for the 1984 Paris Air Show. That year it was ferried to Vandenberg Air Force Base in California to conduct fit checks for Space Launch Complex-6. At the time, NASA was planning on using SLC-6 to launch polar orbiting Shuttle missions [2] but cancelled development after the Challenger disaster in early 1986.

Enterprise sitting on SLC-6 at Vandenberg AFB (NASA)

For the next eighteen years, NASA continued to use Enterprise for testing. One in particular was to plan what to do if the brakes on the orbiter failed. Another looked at the structural integrity of the payload bay doors while still another dealt with mounting an antenna for the Shuttle Amateur Radio Experiment. The orbiter was also used in the wake of both the Challenger and Columbia disaster (2003). The effectiveness and efficiency of various crew bailout procedures were evaluated should an incident similar to what happened on STS-51-L happen again. Enterprise's left landing gear door and part of the port wing were used for foam impact trials to test the hypothesis that Columbia broke apart as a result of insulation foam striking the spacecraft. When not being used by NASA, Enterprise was on display at the Udvar-Hazy Center, an annex of the Smithsonian's National Air & Space Museum. When the Shuttle was retired in 2011, Udvar-Hazy was given Space Shuttle Discovery and Enterprise went to the Intrepid Sea, Air & Space Museum in New York.

Enterprise traveling past the Statue of Liberty on the Hudson River on her way to the Intrepid Sea, Air and Space Museum. (NASA/Bill Ingalls)

Author's Note: Thanks for reading and remember to like and share!

[1] Haise was also the prime commander of Apollo 19 but the mission was cut from the program in 1970.

[2] Vandenberg was the only place in the continental US a polar orbit mission could launch without passing over populated areas.

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Bibliography

• Dunbar, Brian. “NASA Dryden and the Space Shuttles.” NASA, NASA, 11 July 2011, www.nasa.gov/mission_pages/shuttle/flyout/approach_landing.html.

• LiveScience Staff. “How Nerds Named NASA's Space Shuttle Enterprise.” Space.com, Space, 26 Apr. 2012, www.space.com/15454-space-shuttle-enterprise.html.

• Mars, Kelli. “40 Years Ago: Space Shuttle Enterprise Rolls to the Pad.” NASA, NASA, 30 Apr. 2019, www.nasa.gov/feature/40-years-ago-space-shuttle-enterprise-rolls-to-the-pad.