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

[Tulse]

texaslabrat wrote: If the power density of the fusion power sources were sufficiently high (in terms of MW/m^3 and/or MW/kg) , that’s definitely feasible from at least a basic conceptual point of view (ignoring the complexities of the actual aircraft and propulsion system design). A lot of optimization and miniturization of the fusion source will be necessary to make this kind of system do-able for atmospheric flight propulsion.

One of the “advantages” of conventionally fueled craft is that they get lighter as they travel. With a FF powerplant instead, all the weight is constant. I presume there is some crossover point where a specific fixed weight fusion generator is more efficient than than a powerplant running on conventional fuel that gets lighter over time. But it is not immediately obvious that such crossover point can be easily reached — my guess is the fusion plant in such instance would have to be very light relative to its on-the-ground, fixed instantiation.

And I’m still not convinced that there would be any major advantage to such a system. As I noted earlier, the real problem with most launch systems isn’t lack of power per se (at least not power on the scale that an FF device would generate).