wmartin@ALMSA-1.ARPA (Will Martin -- AMXAL-RI) (11/14/86)
Thought SPACE readers might find this item of interest: From DEFENSE ELECTRONICS, Nov. '86, p. 18, "Focus" column: KAMAN'S COIL GUNS PORTEND HEAVY-LOAD LAUNCH ROLE Kaman Corp. of Bloomfield, Conn., plans to build and demonstrate an electromagnetic coil gun under an $8.5-million Army/DARPA anti-armor contract. Using coils instead of rails, Kaman expects to achieve muzzle velocities of 13,000 feet per second and rates of fire of three projectiles per minute. Dr. Henry Kolm, president of Kaman's Electromagnetic Launch Research subsidiary, believes that the coil, not the rail, has the greatest technological potential. He predicts that electromagnetic coils will someday launch aircraft from carriers and spacecraft from launch pads. Aboard cariers, the coils would save space and weight by replacing steam catapults. At the launch pad, according to Kaman's Kolm, electromagnetic coils would initially eliminate first-stage boosters and eventually permit the direct launching of payloads into space. *** End of article ***
kempf@hplabsc.UUCP (Jim Kempf) (11/15/86)
Re: offbeat launching schemes, sometime back I saw an article in a technical rocketry journal about using a space based laser to lift a vehicle using an electromagnetic field and MHD forces. Does anyone know what happened to this idea? Jim Kempf hplabs!kempf
jtk@mordor.ARPA (Jordan Kare) (11/19/86)
In article <869@hplabsc.UUCP> kempf@hplabsc.UUCP (Jim Kempf) writes: > >Re: offbeat launching schemes, sometime back I saw an article in >a technical rocketry journal about using a space based laser to >lift a vehicle using an electromagnetic field and MHD forces. >Does anyone know what happened to this idea? > Jim Kempf hplabs!kempf This may refer to Dr. Leik Myrabo's Apollo Lightcraft project. Myrabo has designed (under contract to the Air Force) a series of laser-propelled vehicles that use several different modes of thrust generation, all powered by a laser beam incident from above. One mode is an "MHD Fanjet", where the laser drives a hydrogen-fuelled "rocket" (laser light passes thru a window and is absorbed in hydrogen gas, which exits thru a nozzle), but the rocket exhaust is used to generate electricity via an MHD system (rather than providing direct thrust). The electricity drives an "electric fan" around the rim of the vehicle: arcs are established between the vehicle rim and an outer shroud ring; blades between rim and shroud contain coils to generate a magnetic field; j x B forces push the arc (and associated air) down and the vehicle up. The advantage is that one gets more thrust than a pure laser rocket per unit laser energy and per unit fuel mass, but can run at higher velocities than any chemical-fuelled jet. Myrabo's systems are ingenious, but complex and untested, with stiff requirements for the driving laser's properties. I recommend his book, "The Future of Flight" (with Dean Ing, Baen Books) for a good collection of exotic propulsion techniques. There are some even more extreme suggestions around (e.g. using the photon pressure of a laser beam in a resonant cavity formed between a vehicle and the ground), but there are also some very simple (though not necessarily straightforward) versions of laser propulsion which may be available quite soon. For instance, a ground-based laser system capable of launching a one ton payload into low earth orbit, at a maximum acceleration of six gees, EVERY 15 MINUTES (uh, lessee, four tons an hour, 96 tons a day, do maintenance on weekends, call it 30,000 tons a year)... System cost less than the Space Transportation System ... unit cost under $50/lb in orbit... When? Maybe before the end of the century. Stay tuned... Jordin Kare jtk@mordor.uucp jtk@s1-c.arpa