It would be fascinating if directed energy could be harnessed in such a way as to allow an aircraft to reach near-orbital velocities within the atmosphere while still “breathing” air. Then as it leaves the atmosphere use a much smaller rocket motor to shape the orbit so it no longer intersected the atmosphere at perigee.
If you’re going to blast an “aircraft” with directed energy, why bother using burnable fuel (therefore breathing air, or carrying LOX) at all in it — just have the arriving directed energy heat up the (optimum kind of) reaction mass aboard the craft to the maximum temperature feasible, then jet it out the back. That ought to allow a specific impulse far better than any burnable fuel could achieve — and then one wouldn’t need a separate rocket engine to use for orbital adjustments in airless NEO conditions at all — because no air is ever required.
Would this make a rail-gun powered launch system feasible for placing structural materials into orbit?
This Looks Like a Blast
I’d say it looks more like: Going On A Tear.
It isn’t as far-fetched as it may sound. When expressed in terms of Crocco’s theorem, the momentum equation contains an enthalpy gradient term which, if manipulated via precisely added enthalpy, can reduce drag to almost nothing.
The Trident missile program accomplished something like this a number of years ago, when they ran hypersonic wind tunnel tests on a model which injected hydrogen into the freestream through the nose aerospike. The drag coefficient was reduced significantly. IIRC, they really didn’t understand why it happened, but it is completely consistent with this approach.
I might add that this, combined with the body-shaping techniques (which prevent shock waves from coalescing, thus reducing the magnitude of the pressure rise) developed in NASA’s low-boom supersonic aircraft program, have a great deal of potential for removing the traditional barriers to high-speed flight.
Sounds promising, keep at it.
It would be fascinating if directed energy could be harnessed in such a way as to allow an aircraft to reach near-orbital velocities within the atmosphere while still “breathing” air. Then as it leaves the atmosphere use a much smaller rocket motor to shape the orbit so it no longer intersected the atmosphere at perigee.
If you’re going to blast an “aircraft” with directed energy, why bother using burnable fuel (therefore breathing air, or carrying LOX) at all in it — just have the arriving directed energy heat up the (optimum kind of) reaction mass aboard the craft to the maximum temperature feasible, then jet it out the back. That ought to allow a specific impulse far better than any burnable fuel could achieve — and then one wouldn’t need a separate rocket engine to use for orbital adjustments in airless NEO conditions at all — because no air is ever required.
Would this make a rail-gun powered launch system feasible for placing structural materials into orbit?
This Looks Like a Blast
I’d say it looks more like: Going On A Tear.
It isn’t as far-fetched as it may sound. When expressed in terms of Crocco’s theorem, the momentum equation contains an enthalpy gradient term which, if manipulated via precisely added enthalpy, can reduce drag to almost nothing.
The Trident missile program accomplished something like this a number of years ago, when they ran hypersonic wind tunnel tests on a model which injected hydrogen into the freestream through the nose aerospike. The drag coefficient was reduced significantly. IIRC, they really didn’t understand why it happened, but it is completely consistent with this approach.
I might add that this, combined with the body-shaping techniques (which prevent shock waves from coalescing, thus reducing the magnitude of the pressure rise) developed in NASA’s low-boom supersonic aircraft program, have a great deal of potential for removing the traditional barriers to high-speed flight.
https://www.nasa.gov/X59