With the high Isp and thrust we could even use a fission reactor
Scientists achieve first-ever plasma ignition in nuclear fusion rocket engine, which can create up to 1,000 times more thrust than standard engines
7 months ago by Innerworld to c/engineering
Semi_Hemi_Demigod 3 points 7 months ago
WoodScientist 7 points 7 months ago
You really don't understand this.
EDIT: actually, I withdraw my comment. In fact it was I that didn't understand. I read your comment as "we could use it as a fusion reactor." A fission reactor would in fact work as the power source as well. You are correct.
Though, the big downside of a fission reactor in space is that you need giant radiators to cool it. In many applications it's probably easier just to use more solar panels and fewer radiators. At least solar panels don't generate tons of waste heat. You still need radiators, but 1 watt of solar power requires one watt of radiators. With a reactor, as its a heat engine, 1 watt of electric power requires 4 watts of radiators.
Semi_Hemi_Demigod 1 point 7 months ago
I’m still a much bigger fan of solar thermal rockets because I’m a sucker for steampunk spaceships with valves and giant mirrors.
But I’m sure there’s a limit where the number of solar panels or giant mirrors is less efficient than a nuke.
The fact that it runs on just straight electricity is what’s really cool about it. As long as you got juice you can store up for a big burn.
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engineering
@sh.itjust.works
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A place to geek out about engineering, fabrication, and design. All disciplines are welcome. Ask questions, share knowledge, show off projects you're proud of, and share interesting things you find.
Rules:
- Be kind.
- Generally stay on topic.
- No homework questions.
- No asking for advice on potentially dangerous jobs. Hire a professional. We don't want to be responsible when your deck collapses.
The community icon is ISO 7000-1641.
The current community banner image is from Lee Attwood on Unsplash.
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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.
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