This is true for traditional chemical propulsion, where you have to get to orbit in a hurry before you run out of cryogenic or hydrocarbon propellants.Re: Role of NTR/BNTR/NEP in future architectures
« Reply #449 on: 06/10/2010 11:28 PM »
--------------------------------------------------------------------------------For a launch vehicle, the first thing you want to do is "get clear" of the atmosphere in your ascent trajectory, so using atmospheric constituents as propellant is counter-productive.Quote from: KelvinZero on 06/10/2010 10:42 PM Im not at all a fan of nuclear launch vehicles, but I have a question,
Why do nuclear and beamed power designs not exploit the atmosphere as propellant?
This is not true for a winged Polywell-powered flying machine using relatively small amounts of H and B11 to heat atmosphere as propellant. Propulsion via p-B11 fusion allows a more leisurely ascent and descent, with indefinite atmospheric cruise before and after orbit.