Boeing X - 20 Dyna - Soar The Boeing X - 20 Dyna - Soar ( " Dynamic Soarer " ) was a United States Air Force ( USAF ) program to develop a spaceplane that could be used for a variety of military missions , including reconnaissance , bombing , space rescue , satellite maintenance , and sabotage of enemy satellites . The program ran from 24 October 1957 to 10 December 1963 , cost US $ 660 million ( $ today ) , and was cancelled just after spacecraft construction had begun . Other spacecraft under development at the time , such as Mercury or Vostok , were based on space capsules that returned on ballistic re - entry profiles . Dyna - Soar was more like the much later Space Shuttle . It could not only travel to distant targets at the speed of an intercontinental ballistic missile , it was designed to glide to earth like an aircraft under control of a pilot . It could land at an airfield , rather than simply falling to earth and landing with a parachute . Dyna - Soar could also reach earth orbit , like Mercury or Gemini . These characteristics made Dyna - Soar a far more advanced concept than other human spaceflight missions of the period . Research into a spaceplane was realized much later , in other reusable spacecraft such as the Space Shuttle , which had its first orbital flight in 1981 , and , more recently , the Boeing X - 40 and X - 37B spacecraft . Background . The development of Dyna Soar can be traced back to Eugen Sänger ' s Silbervogel , a German bomber project of World War II . The concept was a rocket - powered bomber that could travel vast distances by gliding to its target after being boosted to high speed ( > 5 . 5 km / s ) and high altitude ( 50 – 150 km ) by A - 4 or A - 9 rocket engines . Essentially , these rocket engines would place the vehicle onto an exoatmospheric intercontinental ballistic missile - like trajectory and then fall away . When the vehicle reentered the atmosphere , instead of fully reentering , bleeding off its speed and landing , the vehicle would use its wings and some of its speed to generate lift and bounce the vehicle back into space again . This would repeat until the speed was low enough that the pilot of the vehicle would need to pick a landing spot and glide the vehicle to a landing . This use of hypersonic atmospheric lift meant that the vehicle could greatly extend its range over a ballistic trajectory using the same engines . Such boost - glide systems could potentially strike at targets anywhere in the world ( so called " antipodal bombers " ) at hypersonic speeds , be very difficult to intercept , and the aircraft itself could be small and lightly armed , compared to a typical heavy bomber . In addition , a boost - glide aircraft may be recoverable , acting as a manned bomber , or as an unmanned non - recoverable missile . Following World War II , many German scientists were taken to the United States by the Office of Strategic Services ' s " Operation Paperclip " . Among them was Dr . Walter Dornberger , the former head of Germany ' s wartime rocket program , who had detailed knowledge of the Silbervogel project . Working for Bell , he attempted to create interest in a boost - glide system in the USAF , and elsewhere . This resulted in the USAF requesting a number of feasibility and design studies — carried out by Bell , Boeing , Convair , Douglas , Martin , North American , Republic , and Lockheed — for boost - glide vehicles during the early 1950s : Development . On 24 October 1957 , the USAF Air Research and Development Command issued a proposal for a " Hypersonic Glide Rocket Weapon System " ( Weapons System 464L ) : Dyna Soar . The proposal drew together the existing boost - glide proposals , as the USAF believed a single vehicle could be designed to carry out all the bombing and reconnaissance tasks intended for the separate studies , and act as successor to the X - 15 research program . The Dyna - Soar program was to be conducted in three stages : a research vehicle ( Dyna - Soar I ) , a reconnaissance vehicle ( Dyna - Soar II , previously Brass Bell ) , and a vehicle that added strategic bombing capability ( Dyna - Soar III , previously Robo ) . The first glide tests for Dyna - Soar I were expected to be carried out in 1963 , followed by powered flights , reaching Mach 18 , the following year . A robotic glide missile was to be deployed in 1968 , with the fully operational weapons system ( Dyna - Soar III ) expected by 1974 . In March 1958 , nine U . S . aerospace companies tendered for the Dyna - Soar contract . Of these , the field narrowed to proposals from Bell and Boeing . Even though Bell had the advantage of six years ' worth of design studies , the contract for the spaceplane was awarded to Boeing in June 1959 ( by which time their original design had changed markedly and now closely resembled what Bell had submitted ) . In late 1961 , the Titan III was chosen as the launch vehicle . The Dyna - Soar was to be launched from Cape Canaveral Air Force Station , Florida . Design . The overall design of the X - 20 Dyna - Soar was outlined in March 1960 . It had a low - wing delta shape , with winglets for control rather than a more conventional tail . The framework of the craft was to be made from the René 41 " super alloy " , as were the upper surface panels . The bottom surface was to be made from molybdenum sheets placed over insulated René 41 , while the nose - cone was to be made from graphite with zirconia rods . Due to the changing requirements , various forms of the Dyna - Soar were designed . All variants shared the same basic shape and layout . A single pilot sat at the front , with an equipment bay situated behind . This bay contained data - collection equipment , weapons , reconnaissance equipment , or ( in the X - 20X " shuttle space vehicle " ) a four - man mid - deck . A transition - stage rocket engine , located behind the equipment bay , would maneuver the craft in orbit or fire during launch as part of an abort sequence . This trans - stage would be jettisoned before descent into the atmosphere . While falling through the atmosphere an opaque heat shield would protect the window at the front of the craft . This heat shield would then be jettisoned after aerobraking so the pilot could see , and safely land . A drawing in " Space / Aeronautics " magazine from before the project ' s cancellation depicts the craft dipping down into the atmosphere , skimming the surface , to change its orbital inclination . It would then fire its rocket to resume orbit . This would be a unique ability for a spacecraft , for the laws of celestial mechanics mean it requires an enormous expenditure of energy for a rocket to change its orbital inclination once it has reached orbit . Hence the Dyna - Soar could have had a military capacity of being launched into one orbit and rendezvousing with a satellite , even if the target were to expend all its propellant in changing its orbit . Acceleration forces on the pilot would be severe in such a maneuver . Unlike the later Space Shuttle , Dyna - Soar did not have wheels on its tricycle undercarriage as it was thought the rubber would burn during re - entry . Instead Goodyear developed retractable wire - brush skids made of the same René 41 alloy as the airframe . Operational history . In April 1960 , seven astronauts were secretly chosen for the Dyna - Soar program : Neil Armstrong and Bill Dana left the program in mid - 1962 . On 19 September 1962 , Albert Crews was added to the Dyna - Soar program and the names of the six remaining Dyna - Soar astronauts were announced to the public . By the end of 1962 , Dyna - Soar had been designated " X - 20 " , the booster ( to be used in the Dyna Soar I drop - tests ) successfully fired , and the USAF had held an " unveiling " ceremony for the X - 20 in Las Vegas . Minnesota Honeywell Corporation completed flight tests on an inertia guidance sub - system for the X - 20 project at Eglin Air Force Base , Florida , utilizing an NF - 101B Voodoo by August 1963 . Problems . Besides the funding issues that often accompany research efforts , the Dyna - Soar program suffered from two major problems : uncertainty over the booster to be used to send the craft into orbit , and a lack of a clear goal for the project . Many different boosters were proposed to launch Dyna - Soar into orbit . The original USAF proposal suggested LOX / JP - 4 , fluorine - ammonia , fluorine - hydrazine , or RMI ( X - 15 ) engines . Boeing , the principal contractor , favored an Atlas - Centaur combination . Eventually the Air Force stipulated a Titan , as suggested by failed competitor Martin , but the Titan I was not powerful enough to launch the five - ton X - 20 into orbit . The Titan II and Titan III boosters could launch Dyna - Soar into Earth orbit , as could the Saturn C - 1 ( later renamed the Saturn I ) , and all were proposed with various upper - stage and booster combinations . While the Titan IIIC was eventually chosen to send Dyna - Soar into space , the vacillations over the launch system delayed the project as it complicated planning . The original intention for Dyna - Soar , outlined in the Weapons System 464L proposal , called for a project combining aeronautical research with weapons system development . Many questioned whether the USAF should have a manned space program , when that was the primary domain of NASA . It was frequently emphasized by the U . S . Air Force that , unlike the NASA programs , Dyna - Soar allowed for controlled re - entry , and this was where the main effort in the X - 20 program was placed . On 19 January 1963 , the Secretary of Defense , Robert McNamara , directed the U . S . Air Force to undertake a study to determine whether Gemini or Dyna - Soar was the more feasible approach to a space - based weapon system . In the middle of March 1963 , after receiving the study , Secretary McNamara " stated that the Air Force had been placing too much emphasis on controlled re - entry when it did not have any real objectives for orbital flight " . This was seen as a reversal of the Secretary ' s earlier position on the Dyna - Soar program . Dyna - Soar was also an expensive program that would not launch a manned mission until the mid - 1960s at the earliest . This high cost and questionable utility made it difficult for the U . S . Air Force to justify the program . Eventually , the X - 20 Dyna - Soar program was canceled on 10 December 1963 . On the day that X - 20 was canceled , the U . S . Air Force announced another program , the Manned Orbiting Laboratory , a spin - off of Gemini . This program was also eventually canceled . Another black program ISINGLASS , which was to be airlaunched from a B - 52 bomber , was evaluated and some engine work done . This eventually was cancelled also . Legacy . Despite cancellation of the X - 20 , the affiliated research on spaceplanes influenced the much larger Space Shuttle that would also be boosted into orbit by large rockets . The final design also used delta wings for controlled landings . However , it did not fly until decades after the X - 20 program was canceled . The later , and much smaller Soviet BOR - 4 was closer in design philosophy to the Dyna - Soar , while NASA ' s Martin X - 23 PRIME and Martin Marietta X - 24A / HL - 10 research aircraft also explored aspects of sub - orbital and space flight .