Randall Clague wrote: > Dave Weinshenker has a concept for a balloon-launched 4STO built > around HPR motors. They'd have to be custom made, to get the required > mass fraction, but the complexity didn't look to me to be any worse > than HPR stuff that has already flown. I'll let him fill in the > details...
Wasn't balloon-launched, but I did calculate that 4 stages would get you to orbit (in sheer delta-V at least) without pushing too much beyond HPR techology (which is admittedly designed for convenience in manufacture and field use, rather than sheer performance) - I'd have to revisit my calculations, but IIRC it was doable with a stage-to-stage "scale factor" of 4:1, a raw stage propellant mass fraction of 75%, and a specific impulse of something like 240 seconds. (The concept addressed neither the question of the fate of spent stages dropped along the flight path, nor the question of guidance to orbit, so even I am not completely convinced of its feasibility... however, I've thought it would be interesting, one way or another, to do a rough mockup as a 4-stage HPR bird with commercial motors: something like an "L" booster staged to a "J" second stage, and then an "H" and an "F" in the top stages... good luck keeping it in sight!) -dave w _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
