INTRODUCTION to the book Dyna-Soar Hypersonic Strategic Weapons System by Robert Godwin

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Anyone who has followed this series of books may feel compelled to ask the question: Why the Dyna-Soar? They may well even ask: What is the Dyna-Soar?

The main reason for including this particular vehicle in our ongoing series lies in its remarkably foresighted design. Clearly the Dyna-Soar/X-20 was way ahead of its time (even though it was not completed) and that sort of advance in technology is expensive; consuming a sizeable portion of the military budget and employing nearly eight thousand people for over six years. In many ways it has been asserted that the story of the Dyna-Soar began in Austria in the mid-1930’s. It was there in the University of Vienna that Dr Eugen Sänger, a rocket expert, first began to formulate the idea for a winged vehicle that could fly into space and arrive anywhere on Earth in a matter of a little over an hour. If it could be built, the so-called Sänger hypersonic space-plane would be a formidable weapon. On March 5th 1934 Sänger drafted a letter to the editor of the Journal of the British Interplanetary Society stating that he was, “working on extremely fast aeroplanes, rocket-driven.” This was at a time when people who talked about spaceflight were usually considered cranks by the general public and the generous flow of information between rocket researchers was not yet obstructed by politicians or military security.

Just before the outbreak of World War II Sänger was drafted into the Herman Göring Institute and applied his considerable talents to the work undertaken there in various fields of aviation. During the war Sänger and his wife Irene Bredt sat down and wrote a four hundred page report which outlined the concept for the armed version of the space-plane. Now dubbed the antipodal bomber (due to its ability to deliver a warhead to opposite sides of the globe) the concept finally attracted the attention of those who were waging war. Copies of the report were mailed in total secrecy to a handful of the German military elite, including General Walter Dornberger who at the time was commander in charge of rocket research at Peenemünde.

Sänger’s antipodal bomber was to have been pushed horizontally along an almost 2 mile track (sort of like Fireball XL5 or the rocket on When World’s Collide, for those of you who remember such things). The concept for horizontal launch had many advocates at the time because it was a method to reach escape velocity without fighting gravity. After the vehicle raced along the track it left behind a rocket-propelled sled and then subsequently shed its expended rockets and fuel tanks thus decreasing its overall mass. This method was obviously discarded because the vehicle must sustain a constant battle against the denser air at low altitude while it is reaching escape velocity. As anyone who has tried to beat the land speed record can testify, supersonic velocities at ground level are quite hazardous. However there is nothing fundamentally wrong with the principle, it’s just that flying vertically and then gradually tipping over to horizontal once you reach the rarefied upper atmosphere is easier.

Another thing which Sänger realized was that the vehicle didn’t necessarily need a large wing area. He intended to use the wide flat fuselage to provide a substantial amount of the required lift. Lifting bodies and flying wings were all the rage at the time. In England Armstrong-Whitworth were working on their AW-52 flying wing, in the USA Northrup were working towards their YB-49 and in Germany everyone from the Horten brothers to Messerschmitt were working on similar concepts that used unconventional arrangements for increasing lift. Consequently Sänger came up with a design that could have a relatively small wing arrangement with sharp leading edges and a wide flat-bottomed fuselage.

Some engineers have suggested that Sänger was too optimistic when it came to assessing the required thrust to make the vehicle fly. He proposed an engine with 200,000 pounds of thrust but given the overall weight of the vehicle he was suggesting, this may well have been inadequate.

Thankfully it was too late for the Germans to build this super-weapon, even if they could have surmounted the technical obstacles (they were actually contemplating using plain old steel for the fuselage), and so at the end of the war the Sänger-Bredt report fell into allied hands. Soviet leader Joseph Stalin was reported to have been so infatuated with the idea he allegedly dispatched a team which included his own son, to Paris, to find and “acquire” Sänger. The Soviet abduction team failed, and by this time the German rocket scientists who had surrendered to the Americans were already on their way to being fully integrated into the American missile program.

Sänger found himself working in Paris for the post-war French government and somehow was ignored by the contingent of Americans combing Europe for the cream of German aviation talent. He even applied to be taken to America but was dropped out of the running because, under Operation Paperclip, Eisenhower was only prepared to endorse just over a hundred Germans to come and work in America. This oversight ultimately led to Sänger finding himself working in Egypt for a different kind of Nasser! Sänger helped the Egyptians start their rocket program until the Israeli government, recognizing the threat that his ideas posed, demanded that the German government recall him to Germany, a request to which they subsequently acceded. His wife continued her work discreetly from her position at the Stuttgart institute while he spent the late years of his life as Professor of Space Flight Technology at West Berlin’s Technological University. He died at the age of 58 and he certainly knew that his brain-child was beginning to take shape in America without him, since he had declined an invitation to come and join the team at Bell Aerospace, allegedly because the US government would not allow him to bring some of his staff with him.

Meanwhile Walter Dornberger found himself in America. After having his war record investigated by the British he had quickly relocated to Wright Patterson Air Force Base in Ohio before moving on to a consultancy position at Bell Aerospace in Niagara Falls New York. While he worked there he never forgot the Sänger report and by mid-1952 he was lobbying the United States Air Force to approve a series of studies on the feasibility of a long-range space bomber. On July 14th the NACA endorsed the study. Dornberger had made important strides in this direction during the last years of the war with his team at Peenemünde and so he believed that the technological hurdles could be overcome. One of the more difficult obstacles was convincing the American public (and thus the Congress and Senate) that man-in-space was not pure fantasy.

One of the first decisions Dornberger made was to recruit Krafft Ehricke away from the Army Ballistic Missile Division in Huntsville Alabama. Ehricke was an extraordinarily enthusiastic and talented engineer that had been naturalized into the United States under Operation Paperclip. It is interesting to note that between 1952, when Dornberger made his first proposal, and 1957 when the project was suddenly given the “go-ahead” that his old protégé, Wernher von Braun, had managed to launch an extremely well organized campaign (with the aid of Walt Disney, Collier’s magazine and Viking publishing house) to influence the public that a space-faring future was imminent.

A small amount of money was allocated to Bell to pursue their research and a team of engineers were thrown into the deep waters of hypersonic flight. The obstacles were daunting. Requirements included entirely new materials and new ways of approaching the design of the vehicle. All of the disciplines had to be rethought since due to the unprecedented stresses and strains of hypersonic flight the standard approach of building a winged vehicle would be insufficient. The aerodynamic experts had to liaise with the structural and materials experts to try and fabricate something entirely revolutionary. This project brought about a strange confluence of old enemies as Bell assembled a team comprising the best of British (some from the Armstrong flying wing team), American and German engineering talent to continue the search for faster and better vehicles.

The project went through a variety of different names and acronyms, one of which was BoMi, short for Bomber Missile, then there was Brass Bell, a recon version and finally Project ROBO a rocket bomber which was investigated by Douglas, Convair and North American Aviation. In addition it enjoyed a series of speculative launch configurations which included everything from a single stage to orbit to an elaborate three-stage flyback arrangement. In its two stage configuration BoMi was to have a first stage approximately 120 feet in length with a wing span of some 60 feet and a lift-off weight of about 700,000 pounds. Initial discussions for propellants suggested the new hypergolic fuels of nitrogen tetroxide and UDMH. The first stage would have five engines and the second would have three, this was to make sub-orbital flights. A later orbital version would have been 25 feet longer and 240,000 pounds heavier, with the first stage almost entirely built of titanium. (Many years later titanium would be chosen for the United States hypersonic transport which never got off the ground for a similar reason – cost. Titanium is rare and the bulk of the world’s resources are in Russia.) The second stage would almost certainly have employed an ablative thermal protection system (which was to have been sprayed, somewhat in similar fashion to the notorious pink X-15). The payload for the orbital BOMI would have been something in the order of 13,000 pounds.

Dornberger and Ehricke had even suggested a civilian version for long range transportation (see color section). They also planned a variant propelled by liquid hydrogen which made the second stage even larger. This may in turn have led to a three stage version called MX-2276 where the propellant tank was mounted between the flyback first stage and the orbital glider. It was not long before investment questions were being raised about Bell’s ability to cope with such a large program, however somehow the tide remained in Bell’s favor and by 1954 a contract was issued which now proposed a large three-stage vehicle with pilots, orbital capability and a multi-tasking potential.

Two months after the launch of Sputnik the USAF invited contractors to begin work on what had now evolved into a fully militarized project. They would request a sort-of one-man space shuttle. A host of contractors were invited to get involved and indeed everyone from Martin, Boeing, Bell, Goodyear, North American, Lockheed, Douglas, Republic, Convair, Chance and even AVRO in Canada had some sort of orbital hypersonic vehicle on the drawing boards. Some of these companies were not directly involved with the Strategic Systems Division’s request for proposals and just happened to be conducting their own research in the field. A.V.Roe in Canada were already immersed in their Arrow interceptor program and were looking ahead to Mach 3 variants, which inevitably led them further into the field of hypersonics. Indeed the chief structural engineer for Bell’s BoMi program had been recruited from AVRO in 1951. By 1956 the United States government was telling the Canadian government that high speed aircraft were obsolete and that missiles were the way of the future, while simultaneously ramping up the budget for BoMi. Within a couple of years the Canadian government would buy into that myth and would decimate the Canadian aerospace industry by cancelling the entire Arrow interceptor program along with all of its attendant weaponry. Like-minded individuals in some departments of the US DOD would later push the same nonsense at home. It is interesting to note that Canada’s Air Marshall Roy Slemon was at the X-20 roll-out in Las Vegas in September 1962. Slemon had doggedly defended the Arrow but to no avail.

Meanwhile, even though Bell had teamed with Martin to try and cope with the demands of such an enormous project, the hypersonic bomber missile contract would ultimately go to Boeing. Boeing would subsequently christen it the Dyna-Soar (for dynamic soaring) and then later the X-20.

Never before or since was such an expensive program subjected to so many changes in direction. The official Air Force history (page 349) reveals a labyrinth of bureaucratic legerdemain. It seems that the responsibility from the program was shifted on an almost monthly basis for six years. It began life as Sänger and Dornberger’s antipodal bomber but ultimately ended up as a one man test vehicle. This lack of a defined military goal would ultimately be the death of the Dyna-Soar. However the people working on it had aspired to greater things over the course of its life. After the cancellation of the program Lockheed proposed a multi-stage flyback version which would have weighed 28,000 pounds and carried 12 people as well as 6,600 pounds of cargo.

Even the launch vehicle was never truly nailed down. Some advocates at Boeing wanted to use the Minuteman with solid propellant units to launch a smaller glider weighing 6,500 pounds. Before the contract was issued Boeing suggested the Atlas-Centaur but naturally Martin wanted to use their own Titan. Boeing got the glider but were told in April 1960 it was to be launched on sub-orbital trajectories by a Martin Titan I missile. The Titan I had only seen its first successful launch in February 1959 and it did not become operational as America’s largest ICBM until April of 1962. It was 98 feet long and had a diameter which shrunk from 10 feet on the first stage to 8 feet on the second. It used perishable fuels (i.e. kerosene and liquid oxygen) and weighed in at 220,000lbs (without Dyna-Soar). The total thrust of the two stages was 380,000 lbs.

In January 1961 the proposed launcher for Dyna-Soar was upgraded to a Martin Titan II. This new ICBM was first contracted only six months earlier, in June of 1960, and didn’t see its first successful flight until March 1962. It was five feet longer than the Titan I and the upper stage had been widened to make the missile a consistent 10 feet in diameter. The main improvement was the use of storable fuels, a combination of 50% Hydrazine and UDMH with Nitrogen Tetroxide as the oxidizer. Overall thrust was increased to 530,000 lbs but the hypergolic fuels required heavier tanks and so the Titan II weighed in at a hefty 330,000 lbs. The Titan II would go on to become the launcher for Project Gemini.

In July 1961 the Space Systems Division sent in their recommendation to use a version of the planned Phoenix booster called Space Launch System A388. This version of Phoenix would have been powered by solid-rockets on the first stage and the new LOX/LH2 J2 engine for the second stage. Another possibility considered was von Braun’s new Saturn C1 (NOVA) but was eliminated for cost and complexity reasons.

Finally in February 1962 the launcher for Dyna-Soar was upgraded once more for fully operational orbital flight by using a Titan III with its large strap-on solid rockets. The Titan III had been through a couple of early design configurations which used a Martin-Marietta upper transtage (Titan IIIA) and a Bell Agena D third stage (Titan IIIB) before being equipped with two enormous strap-on solid rockets developed by United Technologies. The boosters generated 1.3 million pounds of thrust each, creating a combined lifting thrust of 3.1 million pounds. This enormous booster had little application for delivering warheads (which were shrinking in size and weight) but was suitable for launching military payloads of up to 29,000 lbs into low earth orbit. It was perfect for Dyna-Soar. (Later the Titan IV would increase that payload to over 48,000 lbs.)

Other proposals included one from Martin which was a massive configuration called Boosted Arcturus and would have used a staggering conglomeration of seven Titans strapped together, able to send Dyna-Soar to the moon with 60,000 pounds of payload. Another money-saving version called Project Streamline went back to using the first stage of Wernher von Braun’s new superbooster, the Saturn IB.

There were a variety of still more proposed configurations which all have only one thing in common, they all fully expected Dyna-Soar to sit on top and then fly home to a runway. It was to be the space equivalent of the Swiss Army knife, a tug-boat for Apollo - or a taxi to space-stations - or a bomber for the Air Force – or a spy-plane for the intelligence community.

Since all of these configurations didn’t allow for any kind of escape tower NASA and the USAF began a program at Edward’s Air Force Base in California to try and devise an abort procedure that would allow the crew to escape a bad launch. The experimental F5D aircraft was run through a series of extreme maneuvers by Neil Armstrong until a usable escape path was devised.

Next would have been a series of trials where Dyna-Soar would be dropped from a modified B-52, beginning in early 1965, and then make its first orbital launch in early 1966.

All this is very interesting but the Dyna-Soar was only half-built, and of course it never flew. On that basis it may not seem to merit the attention of an entire book. However, what can be found in the following pages are the details of an audacious program which cost the American taxpayer over $400 million between 1957 and 1963. Some of you may want to know where the money went.

The fact is, even though the Dyna-Soar was cancelled, the spin-offs in experience, materials science and technology were enormous and are still paying dividends today. 36 of the 66 projects were continued, including the pilot controlled booster which was finally used on the Saturn V. Some of the aerodynamic work ended up being used later in an unmanned program called Project Asset which successfully proved the aerodynamics of a similar structure when it flew six times between 1963 and 1965. Dyna-Soar was also the first successful use of Pulse Code Modulation and moreover incorporated a revolutionary inertial guidance system. The glider was to have been an entirely metal structure using the new René 41 alloy for the panels, zirconium for the nose and molybdenum for the hot spots. Because almost all of the effort was spent on figuring out how to bring the glider home and almost nothing was spent on its weapons capability it could be argued that the Dyna-Soar was just a dry-run for the Space Shuttle program. The money spent might therefore be put into that enormous pile where it would almost disappear.

What is particularly interesting are the implications of Dyna-Soar. If it had been seen successfully to its logical conclusion, the United States would have had a space shuttle when the Russians were still trying to launch a three-man pressurized sphere (which was so small they had to do it without the benefit of space-suits.) Apollo might have been accompanied into earth orbit by a sort of one-man companion for support and observation. The International Space Station would not currently be endangered with redundancy due to the lack of an adequate escape system. The enormous amounts of money used to deploy the B-2 (the stealth bomber shaped like a bat-wing that was partially derived from the Northrup flying wing) and the B-1 (variable geometry supersonic bomber) might have been unnecessary, the Dyna-Soar antipodal hypersonic space-bomber might have replaced both and been virtually unstoppable. Now this may seem like Monday-night quarter-backing but the fact is that today these very same plans are still on the table. The USAF are still looking for a quicker way to accurately deliver either a weapon or an assault force to the world’s hot-spots. NASA still needs a life-boat and the Russians are threatening to build what is almost a clone of the Dyna-Soar, presumably based on their own research into such things, to take tourists into space. The problem in 1963 was that no one spent enough time explaining why the Air Force needed a manned space program. As early as September 1961 Secretary of Defense Robert McNamara questioned whether Dyna-Soar was the best expenditure of national resources. Aside from the obvious technological anecdotes associated with the X-20 there are the human stories which involve characters like Dornberger, Sänger, the six pilots chosen to fly it (none of whom made it into orbit although two of them flew the X-15), Mercury astronauts Gus Grissom and Wally Schirra, X-15 pilots Milt Thompson, Bill Dana, Pete Knight and Neil Armstrong (who was one of six pilot/consultants brought into the program.) There is also General Curtis LeMay, an imposing figure in American military history, who urgently advocated the cause of Dyna-Soar, perhaps because he could see that its demise would spell the end of the manned military space program.

By July 1963 a decision had been made that NASA and the DOD would not indulge in any manned space programs without fully considering the other agency's needs. The Air Force announced their long held desire for a manned orbital space station that summer and a plan was evolving, which would use NASA's Gemini capsule on top of the Air Force’ Titan III, to shuttle men and equipment to that station. Dyna-Soar would have been capable of carrying an additional four people in the mid-section (allocated normally for equipment).

Running concurrent to the Dyna-Soar program was the Aerospace Plane program. It began around 1957 and shared many similarities with Dyna-Soar. The original design was to be single-stage to orbit but it evolved into a two-stage flyback version. The second stage of the Aerospace plane looked much like Dyna-Soar but it needed to be powered.

Dyna-Soar, meanwhile, had not originally been designed to be powered so could not carry a large fuel load. Now its mission was no longer as a suborbital glider but a full-fledged orbital vehicle. This meant it would need some kind of de-orbit engine and so the basic shape would have to be changed to accommodate the shifts in the centre of gravity caused by moving fuel. Suddenly versions of Dyna-Soar with engines began to appear in artist’s renderings. Despite all these modifications what would prove fatal for Dyna-Soar was the success of Gemini, the lack of any solid reason from the Air Force to put a manned space craft into orbit and the fact that in 1959 the mandate had shifted from an orbital weapons platform to a suborbital research vehicle and then see-sawed back and forth for the next four years. Politics even intervened when the original landing site for the test flights, in Brazil, was suddenly not available. Consequently too much time was spent on how to get the thing back from space and not enough time figuring out what it would do when it got there. McNamara would not spend the money until some one could tell him what he was getting for it.

On November 25th 1963 the American nation watched in stunned silence as the funeral procession for President Kennedy was televised around the world. Just two weeks later despite the protestations of the Air Force Dyna-Soar was officially cancelled by Defense Secretary Robert McNamara and the new administration of Lyndon Johnson.

The Dyna-Soar story is a tale of high-stakes and high technology involving the leading players in the world of politics and aerospace. Some of the best-known heroes of the American space program played a hand in that story. It is in some ways America’s parallel to the Canadian Avro Arrow story. The Arrow was way ahead of its time and when it was cancelled every working aircraft was destroyed for no logical reason. With Dyna-Soar it was a similar story. Today the only full-size mock-up of Dyna-Soar, built by Boeing, is lost, although a Martin X-23A version (which shows some similarity to the later X-24) built for the World’s Fair still resides at the Oklahoma Omniplex.

This book looks at the story of Dyna-Soar through the official documentation that flowed between the Air Force, NASA and the contractors. There are a few interesting additions such as an article written by Dornberger years after Dyna-Soar was cancelled making a case for the validity of the aerospace plane concept and there is a copy of the bibliography that Sänger used when he prepared his original report. The details of the political machinations can be partially divined from reading these documents but the real narrative is still waiting to be told although an excellent effort was made by USAF Major Roy Houchin for his doctoral dissertation in 1995. This book however is just one chapter in an enormous story that is still being written.

In the end we can only imagine how the geopolitical climate might be different today had the X-20 Dyna-Soar flown in space.