Reply To: EmDrive + Focus Fusion = Space Access for all?

[texaslabrat]

Aeronaut wrote:

I’m not sure that’s true — once in space FF may make technologies like VASIMR far more practical, but the big problem will always be getting into space. I don’t see how FF will significantly change the problems of launching to orbit, at least not without other major technological advances (such as space elevators or huge magnetic launch tracks).

What do you think of a focus fusion powered turbojet/scramjet powered launch vehicle with a chemical LOX/LN2 upper stage glider (type X-33) to fill the gap from high-atmospheric hypersonic flight to orbit?

Fusion-generated electricity drives compressor fans (instead of a turbine) and fusion heated air (instead of fuel combustion) provides jet thrust. Everything fully reusable.

The rocket equation makes it perfectly clear that the space elevator is the enabling technology for meaningful space exploration. My understanding is that raising around 50G$ is a far greater challenge than incrementally increasing the tether strength.

The rocket equation does not pertain to the type of solution that belbear has proposed as the fusion-powered plane would not be consuming a mass-fraction of fuel during the initial ascent/acceleration. For the “booster” phase, yes…but at that point the fuel needed is trivial once the air-“breathing” portion has brought the craft up to the altitude and speed that a scramjet flight regime can provide.

That said, I’m certainly not discounting the usefulness of a working space elevator 🙂