Engineering

For those who want a real explanation for how this can work, and not a fluff piece, you probably will find the article lacking. The first question anyone with more than a single-digit IQ asks about this is, "wait, I thought fusion reactors can't produce net energy, and they're miniaturizing one to fit on a rocket engine? Why can't we just use that as a power plant?"

The answer is that this doesn't actually have to generate net energy. The goal isn't to make net energy. In space, it's easy to get energy. There's constant full sunlight available 24/7. Just put some solar panels on your craft. What this does instead is serve as a very efficient generator of momentum. Ion engines already do this, but this would have both high specific impulse AND high levels of thrust. As I understand it, the idea would be to have solar panels charging up an array of batteries and capacitors. Once those are charged, you then use that energy to power a fusion pulse, superheating the fuel to plasma temperatures and generating absurd exhaust velocities. And some of the energy of the fusion pulse is then recaptured to partially power the next shot. It's not something that would generate net energy. If we can't build a terrestrial fusion reactor that generates net power, we certainly can't do so on a spacecraft. But here fusion is only being used as a powerful momentum generating device, not a net energy device. Solar panels or RTGs would provide the extra energy that the fusion reactor itself can't.