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 X-20A was a R&D program of a military test system to explore and demonstrate maneuvereble re-entry of a piloted orbital space vehicle which will effect a controlled landing in a conventional manner at a selected landing site. The program will gather research data in the hypersonic flight regime, was to test vehicle equipments, will investigate man-mcchine capabilities and represents a fundamental building block for the attainment of future mi litary piloted space capabilities.

The X-20 was the outgrowth of concepts that had begun with Eugen Sänger in 1928 and progressed through the Bell BoMi and RoBo concepts of the 1950s. The program ran from October 1957 to December 1963. The HL-10 and later HL-20 were based on the same concept. By the time the X-15 was rolled out in 1958, the Air Force was already studying the next step in "higher and faster". . . an airplane that would perform a lifting entry from near orbital speeds. This was the X-20, which was conceived in the late 1950s. It started out as a suborbital research airplane and was escalated, conceptually, to an orbital, operational vehicle. The Dyna-Soar a far more advanced concept than other human spaceflight missions of the period. The aircraft was more like the much later Space Shuttle. It was to travel to distant targets at the speed of an intercontinental ballistic missile, reach earth orbit, and then glide to earth like an aircraft under control of a pilot, and land at an airfield, rather than simply falling to earth and landing with a parachute. It eventually was canceled before construction of it was started, as the Air Force geared up to fight the Vietnam War.

In October 1957, the USAF issued a proposal for a "Hypersonic Glide Rocket Weapon System" (Weapons System 464L): Dyna Soar. The new aircraft was expected 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 initiation of the program in November 1957 was preceded by approximately four years of study of methods of extending system performance into the high hypersonic speed flight regime by exploiting large rocket boosters which were under development for the ballistic missile program. It was found that as speed and altitude performance increased, that military potential became of interest. A large number of technicsl problems were identified end found to be of such a magnitude that a research program was required for their solution. After careful study within the Air Force and NASA, it was concluded that the various interrelated problems could best be solved by a research or "conceptual test vehicle" which would be capable of extending the flight capabilities of the X-15 into the high hypersonic flight regime up to orbital speeds.

A Development Directive issued in November 1957 was followed by a competition involving 9 major aircraft companies. From this competition a selection was made of The Boeing and Martin companies to further pursus the relative merits of each company's proposal. During the Phase I competition, both contractors evolved configurations of a wing-body type having very similar characteristics and capabilities. The USAF/NASA evaluation concluded that the Boeing glider design and the Martin booster design should be selected for further development.

During this period, because of extensive NACA interests in a hypersonic flight research aircraft, a joint Memorandum of Understanding was prepared to make the program a joint AF/NASA program. On 20 May 1958 the National Advisory Committee for Aeronautics (NACA) and the Air Force signed a Memorandum of Understanding concerning the principles in the development and testing of the Air Force's Hypersonic Boost Glide Vehicle (Dyna Soar I). The following principles would apply to the project: ( l ) The project would be conducted as a joint Air Force-NACA project. (2) Overall technical control of the project would rest with the Air Force, acting with the advice and assistance of NACA. (3) Financing of the design, construction, and Air Force test of the vehicles would be borne by the Air Force. (4) Management of the project would be conducted by an Air Force project office within the Directorate of Systems Management, Headquarters, Air Research and Development Command. NACA would provide liaison representation in the project office and provide the chairman of the technical team responsible for data transmission and research instrumentation. (5) Design and construction of the system would be conducted through a negotiated prime contractor. (6) Flight tests of the vehicle and related equipment would be accomplished by NACA, the USAF, and the prime contractor in a combined test program, under the overall control of a joint NACA-USAF committee chaired by the Air Force.

By 10 October 1957, the Director of Systems Plans, ARDC headquarters, had completed consolidating the details of the Hywards, Brass Bell, and Hobo programs into a three-step, abbreviated, development plan for the new Dyna-Soar program. A three-step program was devised.

1. Step I utilized the Titan I ICBM booster to boost the glider from Cape Canaveral down the Atlantic Missile Range to velocities of approximately 18,000 ft/sec. While not as high as desired, this speed did permit initial investigation of the high hypersonic heating regime which occurs between 18,000 and 22,000 ft/ sec. Like Hywards, the first phase of System 464L involved the development of a manned, hypersonic, test vehicle which would obtain data in a flight regime significantly beyond the reach of the X-15 and would provide a means to evaluate military subsystems, To avoid further confusion between the purpose of Dyna-Soar and the X-15 vehicles the directorate made a clear distinction between a research vehicle and A conceptual test vehicle. Both vehicles were designed to obtain flight data in a regime which had not been sufficiently well defined; however, the latter was to obtain information for the development of a spcefic system.
2. The second stsp of the three-step program was planned to utilize the same basic glider in conjunction with a lerger, but undefined booster to achieve the orbital velocities necessary for complete re-entry tests. Studies were authorized to examine all possible candidates for this step of the program and to examine possible military equipment tests which could be carried on during the orbital phase of the flights. The Brass Bell program assumed the position of Step II in the DynaSoar plan. A two-stage rocket booster would propel the reconnaissance vehicle to a speed of 18,000 feet per second and an altitude of about 170,000 feet. The vehicle would then glide over a range of 5,000 nautical miles. The system would have to be capable of providing high quality photographic, radar, and intelligence information. The vehicle would also have to possess the ability of performing strategic bombing missions. The Director of Systems Plans considered that the liquid rocket Titan sustainer appeared usable; however, investigations under Step I could prove a fluorine engine more valuable.
3. The third step envisioned future use of the technology developed by the first two steps to develop a weapon system. Step III incorporated the Robo plans, and encompassed a more sophisticated vehicle which would be boosted to 300,000 feet and 25,000 feet per second and would be capable of orbital flight. Like the earlier phase, this vehicle would be able to execute bombardment or reconnaissance missions.

Even though Bell had six years' worth of design studies, the contract was awarded to Boeing in June 1959 (by which time their original design had changed markedly and now closely resembled what Bell had submitted).

Increased glider weight and safety considerations resulted in a change to the Titan II booster in January 1961. This change in boo sters provided a suborbital capability up to 22,000 ft/sec. The MMSP (Manned Military Space Program) study (November 1961) concluded that the best alternative to the current Dyna-Soar program would be to adapt the glider and the Titan III booster together to achieve orbital flight. A ten shot program limited to single orbits was proposed in a development plan dated 16 November 1961, and submittad in conjunction with e White Paper which outlined Air Force objectives in space, and the essentiality of filling the potential critical gap which then existed in the development of controllable maneuvering re-entry vehicles with man integrated into the system. This program was approved in December 1961, and resulted in the initietion of the orbital Dyne-Soar program.

Using a Douglas F5D-1 Skylancer then-NASA Flight Research Center test pilot and future first man on the moon Neil Armstrong developed and flew a launch abort flight maneuver for the US Air Force’s planned X-20 Dyna-Soar space plane. The maneuver was designed to clear the Dyna-Soar from its Titan III booster in the event of an emergency and put the vehicle on a safe approach to a runway landing

The use of the B-70 aircraft as a launch aircraft for the Dyna-Soar space vehicle was investigated in the 16-Foot Transonic Tunnel during Test 177 conducted during 6/21/1961 to 7/14/1961. Dyna-Soar was mounted on the bottom surface of the B-70. This was a concept studied in the late 1950's. The X-20 Dyna-Soar was originally intended to be launched atop a modified Titan II rocket. This concept had the problem of how to rescue the crew in case of a problem on the launchpad. The B-70 configuration avoided this problem by air-launching the X-20 Dyna-Soar at altitude from the B-70 aircraft.

During 1962, two multi-orbit flights were edded within the 10 flight program by direction of Hq. USAF, and a change was later made to utilize the five sesment Titan III booster as a result of a change of the standard booster from four to five solid segments. Scheduled to become operational in 1965, the Titan III would be used to launch the Air Force's X-20 (Dyna Soar) manned spacecraft, as well as heavy unmanned military satellites.

The widely different re-entry durations and heat flux rates for the semiballistic capsule and the X-20 vehicle illustrate the difference in the re-entry hesting problem for the two classes of vehicles. The large heat flux rates associated with cspsule re-entry dictates ablative shields which work well when the re-entry duration is of the order of 10 minutes or less. The smaller heat flux retes of the X-20 vehicle actually result in a greater total hest flux beceuse of the longer duration. However, this heat is radiated away into the atmosphere by the outer skin and only a very small percentage (2 to 5%) is absorbad into the structure.

While the X-20 was still alive, it represented a lifting entry orbital spacecraft for the Air Force at a time when NASA did not have one. On 10 December 1963 Secretary of Defense Robert S. McNamara announced cancellation of the X-20 Dyna Soar project at a news briefing at the Pentagon. McNamara stated that fiscal resources thereby saved would be channeled into broader research on the problems and potential value of manned military operations in space, chiefly the Manned Orbiting Laboratory (MOL) project. These decisions on the X-20 and MOL had been discussed and coordinated with NASA, and, although the Air Force received responsibility for the MOL project, NASA would continue to provide technical support.

In April 1960, seven astronauts were chosen for the Dyna-Soar program: