Reply With QuoteI've read that article before, impressive missile. They should have built that. That thing is made of win.
Vought SLAM (Supersonic Low-Altitude Missile)
Vought SLAM (Pluto)
Overview
Studies of the feasibility of using nuclear power for propulsion officially began in New York City in May 1946 but were moved to Oak Ridge, Tennessee, in September of that year to be at the source of nuclear technology. The NEPA (Nuclear Energy for Propulsion of Aircraft) Project made numerous studies of the direct air cycle in which air is heated by conduction as it passes through a nuclear reactor.
The design of ceramic reactors led to the possibility of a nuclear ramjet with unlimited range. In November of 1955 the U.S. Office of Strategic Development asked the Atomic Energy Commission to determine the feasibility of this concept. By October 1956 the world situation was such that the U.S. Air Force issued a System Requirement (SR #149) for a nuclear-powered winged missile. Further internal Air Force studies and reactor development at General Electric’s Aircraft Nuclear Propulsion Project and later at the Lawrence Radiation Laboratory of the University of California indicated overall feasibility of the nuclear reactor.
The Cold War situation at the time dictated the need for a strategic missile with positive deterrence or retaliation capability. Chance Vought also recognized the need and in 1957 formed a study group under Dr. Walt Hesse to do unfunded studies. These and studies at other aircraft companies resulted in the United States Air Force issuing Requests for Proposal which were sent out to the aircraft industry.
In August 1958, Chance Vought Aircraft, North American Aviation, and Convair were selected to conduct funded studies of a low-altitude nuclear-powered strategic missile for a mission no chemical-powered vehicle could perform.
In early 1961 another competition was held among the three aircraft companies for a contract to study and demonstrate the feasibility of the missile airframe and subsystems. This competition was won by Chance Vought Aircraft and a contract was awarded in April 1961, titled “Aerothermo-dynamics for Pluto”. Pluto was the code name of the ceramic reactor development project then being done at Lawrence Radiation Laboratory.
Studies, design and tests of a nuclear- powered strategic missile weapon system were conducted at Chance Vought Aircraft during the period from early 1956 to mid1964. During this period all the technical unknowns were evaluated and shown to be solvable. A conceptual design of a missile was completed and a test nuclear reactor for propulsion was operated at full power.
Airframe
No airframe had been designed to operate in the environment of Mach 3 at sea level where skin temperatures reach 1,000 Fahrenheit and the sound pressure level is on the order of 162 db. Aerodynamics in this flight regime was little explored. Almost 1600 hours of wind tunnel testing in all the national laboratories resulted in a canard configuration design that could operate in the planned flight profile.
The classical spike inlet was replaced with a scoop-type inlet invented in the program, which gave pitch/yaw performance over a wider range and a pressure recovery of 86% that was much higher than the initial program objective. An extensive materials investigative program resulted in the selection and fabrication of a section of fuselage using Rene 41 stainless steel with a skin thickness of 1/10 to ¼ inch.
This was strength- tested in a furnace to simulate aerodynamic heating. Forward sections of the missile were to be gold plated to dissipate heat by radiation. A 1/3-scale model of the missile nose, inlet and duct was constructed and wind tunnel tested.
A preliminary inboard design of the complete weapon system missile was made to show location of all equipment and hardware, including the hydrogen weapons. A detailed and final design would have been required.
Electronics
SLAM 1/10 Scale Model
Because the SLAM reactor would operate at high radiation levels without shielding, finding suitable electronics that could operate even for the few hours lifetime required was a daunting task. Careful selection and substitution of insulation materials, potting compounds, and semiconductors in a full complement of missile electronics such as guidance and control, telemetry and instrumentation was made with industry assistance.
The largest radiation effects test ever conducted took place in 1964 in the Air Force’s NARF facility at General Dynamics under SLAM Program sponsorship. It was demonstrated that suitable system electronics were or could be made available for the SLAM mission.
Guidance
To deliver multiple warheads with precision over long ranges required a dual guidance system. Inertial systems were available but were not capable of surviving in the harsh radiation environment. The impetus of the program resulted in the development of gas dynamic bearings for gyroscopes, and radiation-resistant, or “hardened” components which were evaluated in the Air Force NARF facility. These tests showed that inertial guidance systems could be made which would satisfy the mission requirements if midcourse and terminal corrections could be made. The Vought- funded studies associated with SLAM developed a precise system for such an application.
This system was patented under the name of FINGERPRINT. The name was changed to TERCOM when the rights were assigned to the U.S.A.F. and is still known today by that name when used in the cruise missile. The system employs terrain contour information along the flight path stored in a digital matrix. A matrix of terrain elevations was concluded to be as distinctive as the human fingerprint. Elevations of all land areas of the earth were available from contour maps. Downward- looking radar on the missile then compares the real elevations with the stored data and the missile position is determined and corrections made to direct it toward the target.
Several TERCOM fixes could be made as SLAM proceeded to multiple targets. Extensive flight testing over all types of terrain, with and without snow cover, verified that accurate missile locations could be obtained. All the required hardware was verified in the NARF facility as being suitable for operation in a radiation environment.
Radiation
The source of energy for SLAM propulsion was to be a nuclear fission reactor operating at a power level of 600 Megawatts. The reactor was not to have radiation shielding for the fission products of neutrons and gamma rays. As a result, the neutron flux was calculated to vary from 9 x 1017 N/CM2 in the aft section to 7 x 1014 N/CM2 in the nose. Gamma ray energy was expected to be 4 x 1011 MEV in the aft section and 1.2 x 108MEV in the electronics compartment.
This required careful selection of materials which could survive not only the high temperatures but also the high radiation levels. The study program investigated all missile subsystems. Some very sensitive ones required a feasible amount of local shielding. The result of the investigations led to the conclusion that missile subsystems were available or could be made available for the SLAM application.
Flight testing of the missile was planned to be conducted over the northwest Pacific ocean with termination in deep ocean waters in the neighborhood where atmospheric testing of nuclear weapons had taken place.
Reactor
The reactor development work for nuclear propulsion systems was started by the NEPA Project and specific development for nuclear ramjet application at the Aircraft Nuclear Propulsion Department of the General Electric Company. As the ramjet program gained in importance, it was moved to the Lawrence Radiation Laboratory (LRL) of the University of California in January 1957. LRL’s working with Chance Vought for missile propulsion requirements resulted in the following nuclear reactor characteristics for the SLAM weapon system:
Diameter----------------------57.25 in.
Fissionable Core-------------47.24 in.
Length-------------------------64.24 in.
Core Length------------------50.70 in.
Critical Mass of Uranium--59.90 kg.
Avg. Power Density---------10 MW/cubic foot
Total Power-------------------600 MW
Avg. Element Temperature- 2,330 deg. F
The fuel elements for the test reactors were made of the high-temperature ceramic beryllium oxide (BO). This was mixed with enriched uranium di-oxide (UO2) in a homogeneous mixture with a small amount of zirconium di-oxide (ZrO2) for stabilization. This mixture in a plastic mass was extruded by the Coors Porcelain Company under high pressure and then sintered to near theoretical minimum density.
Each fuel element was a hollow hexagonal tube approximately 4 inches long, 0.3 inches across flats, and had an inside diameter of 0.227 inches. These were stacked end to end to provide the 50.7 inch length of heated air passage. There were 27,000 of these heated airflow channels and 465,000 individual fuel elements. The design with these small unattached pieces was such that the problems of thermal stress in ceramics was minimized.
Two reactor tests were conducted to verify feasibility. Tory II-A was a scaled-down test which was conducted in mid-1961 and operated at design conditions on October 5, 1961. Tory II-C was a full-scale reactor test for a period of 292 seconds which was the limit of the air supply from the storage facility. That facility stored 1.2 million pounds of air which had to be preheated to 943 degrees Fahrenheit and supplied at a pressure of 316 psi to simulate ramjet inlet diffuser conditions. Tests were conducted at Jackass Flats in The Nevada Test Station by Lawrence Radiation Laboratory. These tests demonstrated the feasibility of the nuclear power-plant for the SLAM weapon system.
The centerpiece of the Pluto effort, the Tory reactor was designed to be durable but compact enough to fly.
The 25 miles of oil well casing needed to store air for ramject simulations dominated Pluto's test site at Jackass Flats.
Mounted on a railroad car, Tory-IIC is readied for its highly successful May 1964 test.
Muscle in Mothballs
All the major areas had been investigated by mid-1964 and the feasibility of nuclear flight was firmly established, laying a foundation for proceeding with a detailed design and flight test. But the world was beginning to change with the Cuban missile crisis in the past, the development of long-range ballistic missiles, and the advent of space exploration. The concept of releasing radioactive fission products in the atmosphere in any locale was being rejected as more was learned of the effects of their release.
The program was terminated in July 1964 by the Department of Defense and the State Department as “being too provocative”. It was believed by many that if the U.S. deployed a missile of such awesome power against which there was no known defense, then the Soviets would be compelled to do so. At the end of the project, Chance Vought had 177 engineers and scientists involved in the program full time. It was called “a model technology program” by the Department of Defense. Much of the technology, especially that of the guidance system, TERCOM, is utilized in the cruise missile that is part of today’s arsenal of U.S. weapons.
Link
Also:
The Flying Crowbar
SLAM (Pluto)
I've read that article before, impressive missile. They should have built that. That thing is made of win.
Interesting idea, I'll grant you but ICBMs were faster (more survivable)Originally Posted by domokun
Would be the basis for a tremendously powerful cruise missile though!
(Although I would recommend a new powerplant, obviously.)
A mach 3 low level missile would be incredibly difficult to intercept. A missile like AMRAAM might hit targets at 50km in a head on engagement, but at low level its max range would be about 20km. Sidewinder at higher altitudes and speeds can hit targets at 20-25km, but at low level its range is about 2-4km. Even the fastest flying interceptors like the Mig-31 and Mig-25 are just supersonic at sea level, so this thing flys 3 times faster.I've read that article before, impressive missile. They should have built that. That thing is made of win.
A large Mach 3 cruise missiles belching radioactive waste would be flying fast enough to knock down some buildings and trees, and the supersonic shockwave at that altitude would smash windows and kill unprotected humans.
Of course the second biggest danger is that it could fly around for years without running out of fuel, spreading nuclear waste and destruction everywhere.
And the biggest danger is if the Soviets had made something similar...
I was trying be sarcastic. That nuclear propulsion was never tested in athmospere for very good reason. It's endurance is very impressive still.
We obviously need a sarcasm smiley...I was trying be sarcastic. That nuclear propulsion was never tested in athmospere for very good reason. It's endurance is very impressive still.
Very true, indeed.
That's a doomsday weapon.... says cap'n obvious.
The technology there could be the basis of the future of Earth to space flight and space to Moon flight I think.
I wonder why they decided to make a bomber, instead of just a bomb.
Why didn't they consider just putting a big thermonuclear warhead in the thing.
The airframe is interesting, though.
probably because they wanted to save money.
I would think a single large warhead that you could deliver to one point and detonate would be a more straightforward task that having this unpiloted bomber flying around, discharging bombs along a route.
yea, but having a separate missile for each warhead would cost much more than a single missile with many warheads.
The USAF doesn't know a damned thing about saving money nor care as far as I'm concerned.
It is a jet. It uses a nuclear reactor to superheat the air, like a jet engine heats the air by burning fuel and heating the air. It wouldn't work in space as there is no air to heat in a vacuum.The technology there could be the basis of the future of Earth to space flight and space to Moon flight I think.
It had to be fairly large but with a nuclear reactor as an engine it was rather expensive. If I remember correctly they ended up wanting to put about 26 nuclear warheads in each weapon and this thing was supposed to fly around the Soviet Union dropping bombs every once in a while over a period of months while irradiating and destroying things with its speed and dirty exhaust. Each missile probably would have cost about the same as building an aircraft carrier at the time.I wonder why they decided to make a bomber, instead of just a bomb.
Why didn't they consider just putting a big thermonuclear warhead in the thing.
A modern nuclear reactor is not cheap. A nuclear reactor back then wouldn't have been cheap either. Even just flying around it is destroying things and killing people with the shockwave and radiation. Taking the time to make a missile that can fly for months or years, and a guidance system accurate enough to hit point targets, why not put a few dozen warheads on it. It is hardly a first strike weapon as we know it today but would be an excellent deterrent.I would think a single large warhead that you could deliver to one point and detonate would be a more straightforward task that having this unpiloted bomber flying around, discharging bombs along a route.
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