At 09:45 AM 2/23/01 -0500, Trei, Peter wrote:

I'll speculate that Jim posted this as a demo that 'amateur' rocketry can reach orbit. If you read the article, you'll find it does nothing of the kind. This is suborbital - in fact, the rocket goes almost 350km straight up and down (they're testing scramjet configurations during re-entry).

A significant portion of a solid rocket motor's weight is the casing and nozzle. The casing allows the gases from the burning propellent to generate enough pressure that when they exit the nozzle their moving a very high velocity. One of the brightest recent ideas in rocketry comes from Technanogy (http://www.technanogy.net): if you reduce the size of the propellent grains the velocity of the gasses at the burning surface can go from sub-sonic to supersonic without the need for a nozzle (perhaps even a casing). Goodbye nozzle and casing, hello single-stage to orbit. Thrust vectoring, if desired, would be accomplished by other well-known means. Technanogy has built a pilot plant to manufacture 40 nm aluminum powder. The technology's efficacy was verified by a series of test at Aerospace Corp. and they have secured a grant to retrofit a large number Sidewinders. They claim that the change should dramatically increase range with minimal weapon system changes. If successful they hope to apply their approach to orbital vehicles. steve