dietz@SLB-DOLL.CSNET (Paul Dietz) (01/21/86)
Here are some more thoughts on possible technologies for cheap ground based high acceleration launchers. Ramrod: this is a DARPA-funded program developing a self-igniting scramjet propelled antitank projectile. It would be fired from a conventional cannon, ignite and accelerate up to Mach 5. Conventional antitank rounds travel at perhaps mach 3-4 after leaving the barrel and decelerate quickly. It seems to me the same idea could be applied to projectiles launched into space. The projectiles will have to be coated with ablative materials anyway, so it may make sense to use the lost mass as jet fuel. This may also help keep the projectile velocity down when travelling through the lower atmosphere, and may make more depressed trajectories feasible. This also suggests a hybrid cannon/rocket scheme. The projectiles are streamlined and somewhat smaller in diameter than the cannon bore. The projectiles carry some fuel, maybe hydrogen or methane. The cannon is filled with cold oxygen gas. As the projectile flies down the barrel oxygen slips past and is mixed with fuel, then is shot out the back. The region between the projectile and the wall forms a combustion chamber. Very high accelerations would be needed (> 1000 gees) which may mean too much heat is generated to be practical.