Cold War History Declassified

Project Whitehorse - Neutral Particle Beam.

Westinghouse "KEMPSTER A" device mounted on A-12 131 or tests, which generated an electron cloud to reduce radar reflections.



Of the details I've been able to find, Kempster A was >250lbs per gun and "high power requirements". This was probably the 150Kev and 80MA gun, producing cones of ionized air ~300ft outward from the chines.

Kempster B was a pulsed gun. Haven't found anything more than that but it was likely much lighter and smaller than A. One report mentions a weight under 90lbs per gun being possible with further development, and ~78lbs an optimistic but achievable weight with more funding.


For x-ray shielding there is a report that makes estimates for required lead thickness in the q-bay. This is highly dependent upon what film was being used. 4404 needing none, SO-206 would have some fogging without shielding, 4400 needed 0.6mm of lead on the aft bulkhead and 4401 required double that.

Oh and there are quite a few flight reports that confirm flight testing. Very likely that Kempster A and B were flight tested based on the dates of these tests.

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The AIRS (Advanced Inertial Reference Sphere) made GPS redundant before it was even invented, or it would have were it not so damn expensive.

AIRS is a Fluid-suspended gyrostabilized platform system, as opposed to one using a Gimballed gyrostabilized platform. It consists of a beryllium sphere floating in fluid. Jet nozzles are used to stabilize the inertial platform as commanded from the sensors. This design not only eliminates the problem of gimbal lock, but also makes it extremely accurate (drift less than 1.5×10−5 °/h), accurate enough so any further improvement would give a negligible benefit to the missile's CEP.

In fact, had the AIRS been small enough to fit to MaRV warheads, they would have been accurate to ~1.8m over a 14,000km, 30 minute flight.





Martin-Marietta Zenith Star. Hydrogen fluoride laser (2.7e-6 m, 2700 nanometers near infrared), about 2 MW. 2 meter radius mirror. Maximum effective range about 300 km. 4.6 m diameter, 24.8 m long, 39,000 kg. At 300 km spot size is 0.25m radius, brightness is 10.4 MW/cm2 or 1.04 kW/cm2.

The Strategic Defense Initiative of the 1980's and early 1990's produced a large number of designs for launch vehicles and spacecraft. However, due to the security classification clamped down on much of the work done, relatively little of these designs has come to light. We are generally left with a smattering of artists impressions and sketches, with some often contradictory and usually not very informative descriptions.

SDI was aimed at producing a "missile shield" able to defend the United States from a Soviet nuclear attack. Neutral particle beams, nuclear-pumped X-ray lasers, railguns, space-based missiles, ground based missiles and other science-fictiony technologies were all studied in some depth, with various levels of development. One of the more popular technologies, at least one of the more publicly visible and discussed, was the space based laser.

Several types of laser are possible, with chemical lasers — deriving their vast power from the reaction of chemicals such as chlorine, fluorine and hydrogen — being among the most powerful, reliable and well understood. But even though such lasers had been built and demonstrated on the ground, actually reliably operating one in space, targeting warheads thousands of kilometers away, would require a great deal of development. And thus in 1987 the DoD began the Zenith Star program, aimed at orbiting a space based laser test system.

Zenith Star, as designed by Martin Marietta circa 1988, was a two-component vehicle. The aft spacecraft was the Alpha laser, which combusted fluorine with hydrogen to generate around 2 megawatts of laser light; the forward spacecraft would contain the optics (including a 4-meter diameter main mirror) and aiming system, turning the beam of light from the Alpha laser into a tightly focused "ray" aimed at the target 60 to 300 kilometers away.

Zenith Star was expected to fly in the mid 1990's, and, if successful, could have led to an operational space based laser around 2000. The collapse of the Soviet Union ended the threat of global thermonuclear war and ended support for the program.

Each of the two Zenith Star components was to be launched atop a Titan IV booster. Alternative concepts called for launching the spacecraft as a single unit; in order to do this, a heavy lift booster would be needed. The Zenith Star Launch System was thus proposed, a new vehicle built from existing components such as the five seven-segment boosters from the Titan IV and a larger diameter Titan core with 5 LR-87 engines. Additionally the complete Zenith Star could be launched by a Shuttle C; the Zenith Star diagrams here were created in large part from a Shuttle C/Zenith Star configuration. Details of the Zenith Star are, perhaps unsurprisingly, hard to come by. The spacecraft is 15 feet in diameter and 81.25 feet long. Weight for the single-launch vehicle is given as about 86,800 pounds.


On Nov. 24, 1987 during a visit to the Denver-based Martin Marietta Astronautics factory, President Reagan revealed for the first time the full dimensions and advanced status of the Zenith Star space-based laser demonstration project, a model of which is pictured on this page. Zenith Star is the Strategic Defense Initiative (SDI) continuation of the Defense Advanced Research Projects Agency space-based chemical laser program. The two major elements of Zenith Star are the LAMP mirror and the Alpha chemical laser, both of which elements have been demonstrated in laboratory experiments shown in the photographs.

The SDIO has already awarded Martin Marietta, together with its primary subcontractors, Lockheed Missiles and Space Company and TRW, a Phase II contract for demonstrating the feasibility of a space-based laser experiment. The Alpha laser program is the most mature of the SDI's directed energy technologies. It is developing and validating key critical technologies neede to establish the feasibility of space-based ballistic missile defense.

The simplicity of Alpha's construction and operation makes it a strong candidate for strategic defense. The Alpha laser system is constructed primarily of extruded aluminum, and derives its beam from a purely chemical reaction, which is also the primary source of energy for the laser. Tests have established that Alpha can prov'de the technology to realize sufficiently high power chemical lasers for strategic defense.

The Alpha is the follow-on to the MIRACL (Mid-Infrared Advanced Chemical Laser). On Sept. 6, 1985 the MIRACL laser destroyed the second stage of a Titan I booster in tests conducted at the High Energy Laser System Test Facility at the White Sands Missile Range in New Mexico.

The Alpha program is managed for the SDIO by the Air Force Weapons Laboratory. The prime contractor is TRW, Redondo Beach, California.

The second major element of Zenith Star is LAMP (Large Advanced Mirror Program), shown in the third photograph. This program has demonstrated mirrors which are light enough to deploy in space. LAMP is the culmination of a decade and a half of R&D effort.

The LAMP mirror is being used to study technology issues involved in utilizing large optics for strategic defense applications. Performance tests of the LAMP mirror will be completed in early 1988. The successful demonstration of this segmented LAMP mirror removes one of the major technology barriers to developing directed energy weapons.

The LAMP program element is managed by the Rome Air Development Center. The rime contractor for the project is ITEK Corporation. Eastman Kodak fabricated the LAMP mirror's center segment.


The LAMP mirror is an adaptive, segmented mirror currently in final stages of acceptance testing by lTEK Corporation of Lexington, Massachusetts. Here a technician checks the mirror surface after the seventh and final segment is in place on the supporting backplate. The extremely precise figure (shape) and alignment of the mirror's lightweight facesheets are controlled by actuators attached to the rear surfaces. The overall diameter of the fully assembled mirror is four meters.


The cylindrical gain generator of the Alpha chemical laser is prepared for installation and testing at TRW's Capistrano Test Site. Alpha uses atomic fluorine and h drogen to form the hydrogen fluoride lasing medium. The evice then uses cylindrical mirrors to extract a 2.7 micrometer wavelength high-power laser beam. Alpha is the key component in the concept design for the SDIO's Zenith Star experiment.
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