The shuttle’s story dates back to before WWII, when an Austrian engineer named Eugene Sänger put pen to paper and outlined the principals of hypersonic flight. Sänger had written a report for the Luftwaffe which proposed a rocket plane with a dry-weight of 20 tons and a payload capability of 80 tons. To get such an enormous load off the ground presented the same problems as it does today. Sänger suggested a straight takeoff track over three kilometers long. His subsequent report ended up on the desks of, amongst others, Wernher von Braun, General Dornberger and Soviet dictator Joseph Stalin. At the end of the war, Sänger’s ideas were part of the treasure trove appropriated by the allies and, despite Stalin’s best efforts to locate the Austrian genius, Sänger lived on to a ripe old age in the West.
By the 1950’s Wernher von Braun and many of his team had integrated into American society and were working towards their dream of colonizing space. Due to the frosty political climate prevailing between the West and the Soviet Union, von Braun was encouraged to spend his efforts on building bigger and faster ways to deliver a nuclear warhead to Moscow. The ICBM became the preferred big money project, but Sänger’s work was not forgotten and the possibilities of hypersonic winged flight continued to be explored in the high California desert. By 1959 the culmination of these efforts produced the X-15 rocket plane which flew to altitudes of over 60 miles and tested the concepts of winged reentry as well as the idea of using ejectable fuel tanks. The X-15 landed as a glider back on the runway at Edwards Air Force Base under the control of the pilot.
On April 12, 1961, the rules of the game changed when the Soviets launched a Vostok capsule to an altitude of 203 miles. Yuri Gagarin had been strapped on top of an R-7 ballistic missile. Sputnik had proven three years earlier that the Soviets could drop a bomb anywhere they wanted, but Vostok 1 proved that a man could survive the dramatic and punishing forces atop a missile. At this moment winged spaceflight took a giant leap backwards. The Space Race was fully engaged and missiles were now the order of the day. Reusability was quickly forgotten. For the next decade the hypersonic revolution wallowed in the backwaters of obscurity in the deserts of California.
Just as April 12, 1961, had been a bad day for winged spacecraft, July 20, 1969, was a good day. As history will never forget on that day two men stepped out on to the lunar surface and effectively ended the space race in dramatic style. In a moment of incidental irony it is often forgotten that the first of those men, Neil Armstrong, had spent most of his early career as one of a handful of test pilots flying the X-15, at that time the world’s only winged spacecraft.
Less than two weeks after Apollo 11’s crew returned to a triumphant welcome, Wernher von Braun made a presentation to the Space Task Group about the future of manned spaceflight. In von Braun’s version of things the enormous Saturn V and a newly proposed winged Space Shuttle would combine forces. These two heavy lifters would be used to build space stations, moon bases and even permanent settlements on Mars by 1986.
This wildly optimistic vision would be stymied by everything from politics to oil embargoes. President Nixon wanted a cheaper an less audacious plan that did not include the continuing production of the mighty Saturn rockets and in which these lofty goals would be considerably restrained. Reusability became the name of the game and the only way to make a spacecraft reusable was to put wings on it. Suddenly the pilots of the Mojave were pushed into the limelight.
On August 12, 1977, two men, ex-Apollo 13 astronaut and Edwards test pilot Fred Haise and co-pilot Gordon Fullerton sat at the controls of the first Space Shuttle, named Enterprise. Carried aloft to an altitude that would have Monsieur Rozier gasping for breath, Haise and Fullerton launched the 90-ton glider away from its carrier plane and into the history books. In just less than six minutes Haise and Fullerton brought the 180,000 pond glider to a perfect landing on the desert runway.
After a handful of similar test flights, which Haise and Fullerton shared with another X-15 pilot, Joe Engle (and his crewmate Richard Truly), the Enterprise was shipped off to Florida. A series of further tests ensued which saw the orbiter mated to its fuel tanks and strap-on boosters.
On April 12, 1981, two astronauts climbed aboard the fully fueled and integrated Space Transportation System, Columbia STS-1. John Young, a veteran of both Gemini and Apollo, and Robert Crippen had been selected to take the shuttle on its first full flight into space. Twenty years earlier on the same day a Russian missile had propelled 10,395 pounds into space using 1.1 million pounds of thrust. Gagarin flew 25,000 miles in 108 minutes. On this day 180,000 pounds would ride atop 7.7 million pounds of thrust, an increase in engine and fuel efficiency of over 300 percent. However, this crew would be landing on a runway after traveling over a million miles in a little over 54 hours.
Today the Space Shuttle still stands at the top of the list as the greatest flying machine ever built. The wildest imaginings of Monsieur Rozier could not have envisioned the Space Shuttle, and yet, only 150 years after his immortal flight Eigen Sänger’s sketches laid the foundation for the reality we know today.
When NASA decided at the end of the Apollo Moon program that it needed something new for future space travel, various concepts were proposed – and from those emerged the Space Shuttle. North American Rockwell was given the prime contract in July 1972 to build five Space Shuttle orbiters, the first one being a prototype to be used for glide and ground tests. Work to build the first shuttle orbiter, OV-101, began on June 4, 1974, at the Rockwell’s Air Force Plant 42, Site 1, in Palmdale, California. Final assembly of all the components that came from various subcontractors started in March 1975. On August 25, 1975, the final assembly was complete.
At Christmastime 1975, readers of the trade journal Astronautics & Aeronautics saw an arresting color photo on the cover of the January 1976 issue. It showed what was unmistakably an airplane in final assembly within a hangar – and which equally unmistakably was a Space Shuttle orbiter. “Space Shuttle 1976,” read the cover’s caption; “Into Mainstream Development.” The wings and vertical fin were in place, along with much of the fuselage. This was OV-101, which later that year – as a result of the mail campaign organized by fans of the popular Star Trek TV series– was to receive the name “Enterprise.”
The Trekkers had only forgotten one thing – Enterprise was not built to fly in space like the “real” starship. But nonetheless she had a useful career in flight and ground test. In September 1976, amid considerable ceremony, she was rolled out for public display, thus showing dramatically that the shuttle program indeed was building hardware.
During the summer of 1976, shortly before the rollout, OV-101 had served as the test vehicle for the Horizontal Ground Vibration Test, conducted in Palmdale. Earlier vibration testing had used an accurate structural model, at one-quarter scale, with water in its External Tank to simulate liquid oxygen and air replacing the very lightweight liquid hydrogen. The new tests gave engineers their first opportunity to verify their mathematical models by taking data on the structural dynamics of an actual flight orbiter.
Although OV-101 was not identical to the configuration planned for OV-102, the differences were well understood and accounted for in the model. For instance, Enterprise did not have provisions for mounting real OMS pods, but used structural boilerplate replicas, and the vertical stabilizer was built-up using skin and stringers as opposed to the integrally machined structure of OV-102. The payload installed in the orbiter during the HGVT was the 10,000-pound Development Flight Instrumentation package that would be used during the atmospheric flight tests.
There were two test configurations, one with the orbiter supported in a “free-free” condition to simulate reentry and landing, and the other with the orbiter rigidly attached to the ground at its External Tank supports to represent the configuration during ascent. Tests were also conducted with the payload bay doors opened to simulate an on-orbit configuration. Ferry locks were used to secure the aerodynamic control surfaces during testing, mainly to prevent unexpected damage. The tests vibrated this vehicle at frequencies from 0.5 to 50 hertz, determining natural or resonant frequencies and their damping. Other measurements determined frequency response at the locations of sensors used for guidance and control. Following the completion of the tests, minor modifications were made to the vehicle prior to the public rollout.
The following year Enterprise would be used for Approach and Landing Tests at Edwards Air Force Base, California. It would be flown piggyback atop the SCA Boeing 747, later to be used to ferry orbiters from coast to coast, and released, gliding back to a landing as if returning from space. Following the ALT flights, OV-101 continued to find useful roles, first in structural tests and then in exercising the shuttle’s launch facilities, and for a short while even in “diplomatic” service.
She was not much of a starship. By comparison with later operational orbiters, Enterprise was little more than an aluminum shell swathed in Styrofoam. She lacked all propulsion; the main engines, orbit-maneuvering engines, and attitude-control thrusters were dummies. In place of her thermal protection, blocks of polyurethane foam covered the surface. The nose and wing leading edges, which would be of temperature-resistant carbon-carbon composite, instead were of glass fiber. Enterprise had fuel cells for onboard power, but these held their hydrogen and oxygen as gases in high-pressure tanks, not as liquids in cryogenic dewars. Hence they could not run for very long.
The flight deck lacked many instruments and displays that would be needed for ascent to orbit. Most of the navigation, guidance, and propulsion controls were missing, along with the star tracker controls. The heads-up displays were not installed, nor were all then panels, switches, and indicators for the ET and SRB systems. A small amount of additional instrumentation was added just below the left display electronics unit for the air data system installed on the long flight test boom on the nose.
Three cameras recorded the pilots’ actions and Lockheed SR-71 zero-zero ejection seats were provided in the vent escape was necessary. Two blow-out panels were installed above the pilots to facilitate ejection, or rapid egress on the ground. The two windows looking from the aft flight deck into the payload bay were absent, covered by aluminum panels, as were the overhead rendezvous windows. Aluminum braces were installed where the middeck airlock should have been.
The crew quarters needed such amenities as the galley, the waste management system, and middeck lockers. The payload bay was not fitted out to accommodate its payloads, while the bay’s doors had no hydraulics and no radiators to get rid of waste heat. In flight, the crew was to lower the landing gear by triggering explosive bolts and letting gravity do the rest. But this gear lacked a hydraulic system for retraction.
Even so, Enterprise looked like a Space Shuttle and she held more than outward show. For the moment, she was well-suited to do her limited purpose. After the second rollout on September 18, 1976, where she had gone on display at an open house for Rockwell employees, she returned to her hangar for checks of her onboard systems (yes, she did have them).