The Flight of the X-1
About eighty miles north of Los Angeles, the small town of Rosamond slumbers on the edge of the Great American Desert. Here the air is thin and cold, and the smog behind you in the LA basin is an orange-tinted shroud between the high peaks of the Sierra Nevada and the breakers of the Pacific Ocean.
Outside the town, to the north-east, the sand-blasted landscape stretches to a limitless horizon. The only things to break the monotony are the tormented silhouettes of the Joshua trees that stud the landscape like arthritic corals. Yet, believe it or not, there are lakes here – Rosamond Dry Lake and Rogers Dry Lake.
The water in the lakes exists for only a few months of the year when the small amounts of rain that fall during the winter months are washed back and forth, back and forth, until the beds of these lakes become perfectly smooth and level. In the summer, the water evaporates and the furnace sun of the California desert bakes the mud until it is as hard and smooth as glass. Here, nature has created America’s greatest natural landing field.
It is no surprise therefore that in the years following the end of the Second World War the US Army Air Force (later renamed the US Air Force) chose this place to test its new jet and rocket planes. There were thousands of square miles for error and – given the fickle nature of some of the beasts that were put through their paces here – that was just as well.
In the beginning – before the USAF had been formed from the US Army Air Force – this airfield in the high desert had been named Muroc.
It first achieved fame at 1015 PDT on October 14 1947 when Charles E. “Chuck” Yeager became the first man to fly faster than the speed of sound – breaking the sound barrier in the Bell X-1 rocket plane. By pushing Newton’s laws of action and reaction to the limit, the flight made Yeager and Edwards Air Force Base (as it was eventually renamed) famous in the world of military aviation.
The tradition established by Yeager and the X-1 leads directly to the fabled X-series rocket planes – of which the hypersonic X-15 rocket plane (as seen in the opening credits of First Man) is the most notable example – and thence to the Space Shuttle.
The X-15 set speed and altitude records in the early 1960s, reaching the edge of space and returning with data that was essential to the development of future high-speed vehicles, particularly those intended to fly back into the atmosphere, such as the Space Shuttle. Today the X-15 still holds the record for the fastest speed ever reached by a piloted rocket-powered airplane.
In the early days of the Space Age, the Air Force and NASA had established a convention that the edge of space was at an altitude of 50 miles (80.47 km, 264,000 ft). Pilots who flew above this altitude were eligible to wear astronaut wings. During the X-15 program, eight pilots reached this altitude, qualifying them for astronaut status.
The lifting bodies were a breed of experimental aircraft that complemented, then succeeded, the X-15. They were to explore a third area of aerodynamic engineering which was very different to the existing winged variety of conventional aircraft (including the X-15) and the ballistic capsules of the Mercury, Gemini and Apollo spacecraft.
The latter programs were an attempt to catch up with the Soviets after the surprise launch in the fall of 1957 of Sputniks 1 and 2. So worried were the Americans by what they perceived as a ‘missile gap’ that they decided to abandon the orderly progress by which the X-15 would lead to a winged space plane. Instead they decided to go with the so-called ‘Man-in-Space-Soonest’ concept. This would use a modified ballistic missile to launch a capsule containing a man (Mercury) and eventually men (Gemini and Apollo) into orbit and from there to the Moon. It was a ‘quick and dirty’ approach that would cut years of development off putting Americans into space. Ultimately this approach would pay off on 20 July 1969 when Neil Armstrong and Buzz Aldrin walked on the Moon.
In the meantime, progress towards a lifting re-entry vehicle such as the Shuttle was not completely shelved, but there were still many engineering problems to be overcome. Chief among these was the fact that a reusable spacecraft with wings would experience severe heating and structural stresses particularly at launch, re-entry and landing. On the other hand the Shuttle would need wings to achieve a useful cross range during re-entry and for landing.. For the return to Earth the vehicle’s wings also would have to be designed to withstand the extreme dynamic and thermal stresses of hypersonic speeds. Chuck Yeager may have taken the X-1 to just beyond Mach 1 but the re-entry speed of the Shuttle would be close to Mach 25 (17,500 mph).
Thus, despite the fact that Wernher von Braun’s original concept for a reusable spacecraft (which dated back to the 1950s) was explicitly a rocket with wings, it seemed that his solution on its own would not work. But by the 1960s it was realized that the challenge of lifting flight through the atmosphere might be met by with a hybrid approach combining wings with a lifting body fuselage. The Shuttle was, in fact, a more refined application of an older concept, dating to the work of Eugen Sanger and his wife, mathematician Irene Sanger-Bredt, who had first conceived the classic flat-bottom half-ogival body shape, coupled with wings, for their so-called “Silbervogel” space transportation system first proposed in the late 1930s. Where the Shuttle differed was in more careful blending of the wing and body, and use of a large delta wing as opposed to conventional straight wings with a conventional tail, as the Sangers had envisioned.
NASA began flight-testing experimental lifting bodies at Edwards in the 1960s, following evolution of the concept earlier in the 1950s. A lifting body is a fuselage that generates lift at the expense of higher drag. It uses a modification of the “blunt body” principle developed by H. Julian Allen at NASA’s Ames Research Center. Allen had showed in the early 1950s that a blunt body produced a detached shock wave that carried away ninety percent of the heat of re-entry. A lifting body is a tailored blunt body shape that uses this principle to survive re-entry, but which also has a high degree of streamlining and shaping so that it can generate lift, and fly through the atmosphere, rather than plunging through it like a capsule. This hybrid approach optimises all phases of flight – subsonic, supersonic, and hypersonic, including spacecraft re-entry. All of these flight regimes are required for a true space plane.
The lifting body research was conducted at NASA’s Dryden Flight Research Center based at Edwards. The engineer in charge was Dale Reed, whose first full-size model was the NASA M2-F1, an unpowered craft based on an Ames body shape but made of wood. Initial tests were performed by towing the M2-F1 along an Edwards dry lakebed behind a modified Pontiac Catalina. The M2-F1 was soon nicknamed the “Flying Bathtub”.
In 1966, NASA began test flights with heavier rocket-powered lifting bodies which were air-launched from under the wing of a B-52. All used the XLR-11 rocket engine that Yeager had used on his epochal flight. The Northrop HL-10, and the Air Force -24A and X-24B were just some of the weird and wonderful designs that were tested. Most of the general public had never heard of these lifting body designs until watching the 1970s television show “The Six Million Dollar Man” in which real footage of the test pilot Bruce Petersen showed him crashing his Northrop M2-F2 after a combination of high pilot workload and stability and control problems caused it to ‘auger in’ (in flight test parlance) to the baked desert floor at Edwards.
The lifting body experiments were vital. Dr Richard Hallion, a specialist in the history of the X vehicles, told me, “They gave us critically important information on how pilots could function in a near-space (X-1, X-2, and D-558-2) and transatmospheric space (X-15) environment, and also insight into the challenges of piloting a low-lift-to-drag ratio lifting re-entry vehicle down to a precision landing (X-15, M2F-2/3, HL-10, X-24A/B). [On top of that] they also gave insight into the operational problems, challenges, and nuances of rocket-propelled aircraft.”
Building the Space Shuttle
NASA formally adopted the Shuttle program in 1969 during the heady days of the Apollo program’s first success. Two NASA centers – Marshall (Huntsville) and Johnson Space Center (Houston) – oversaw the construction of the Space Shuttle which was built by Rockwell in California. Essentially the orbiter was comprised of four main subsystems; solid rocket boosters, external tank, main engines, and orbiter. Marshall, the technical home of Wehner von Braun, oversaw the construction of all but the orbiter, which was designed by Houston.
It was envisaged that the main role of the Space Shuttle would be servicing a large civilian space station that would be funded at a later date, perhaps sometime in the 1980s. But in the late 1960s a military station – the Manned Orbiting Laboratory (MOL) – was already being designed by the Air Force. A team of fourteen military pilots were in training to fly the Shuttle to and from the MOL, one of whom was former Naval Aviator and Edwards Test Pilot School alumnus Bob Crippen. In 1967 Crippen and the other astronaut candidates for the post Apollo era had been given a stark choice – choose between the DOD or NASA. Since NASA’s future beyond Apollo was uncertain (the Space Shuttle would not be green-lit until 1972), Crippen made the decision to go to the DOD to work on the MOL program. But, in a date that is clearly engraved on his mind, he told me that the MOL project was canned on June 10 1969 – only a month before Armstrong and Aldrin would walk on the Moon. The cancellation of the MOL projects was a direct consequence of the costs of the MOL program and the inescapable fact that advances in technology were already showing that machines could soon perform many of the tasks that had been envisaged for the military personnel aboard MOL.
In a bitter blow to Crippen., Deke Slayton, then Director of Flight Operations, told Crippen that now that the Apollo program was finished he did not have anything for him to fly – and Crippen knew that the Space Shuttle would not leave the launch pad until at least 1980. So there were many long years to fill. But Crippen put them to good use. As the years went by and the Space Shuttle meandered through its long development, Crippen worked on the projects that were spun out from Apollo – Skylab and Apollo-Soyuz. Crucially, he also worked on the vital heart of the Space Shuttle – its computer systems. By the time the Space Shuttle was almost ready to fly, John Young had taken over from Tom Stafford (Commander of the Apollo-Soyuz mission) as the Chief of the Astronaut Office and he and Crippen were working together. It was an association that was to develop into friendship. As Chief Astronaut it was likely that Young would be commander of the first mission. But Crippen was still bowled over one afternoon, while he was waiting with Director of Flight Operations George Abbey for the arrival of Enterprise (the version of the Shuttle that was used for landing tests) at Ellington Air Force base. Abbey said to him “Crip, how would you like to fly the first Shuttle?” As Bob Crippen told me, he was ready to turn handsprings at that point.
Crippen was appointed Pilot on STS-1 – the inaugural Shuttle flight and the Commander – as he had correctly predicted – was John Young. It was almost time for the first launch of America’s first reusable spacecraft.
Copyright Richard Corfield. All Rights Reserved.