a ship idea I have been toying with, comments welcome

Afraid I have no idea how far out the rings would have to be to avoid being consumed by the mini-sun they've created ... but other than the "rings" design architecture, how is it different/better than a "regular" contained fusion reactor?

And ... interesting to hear a question about fusion starship design coming from Iraq.

How ironic would it be (story idea?) if all this brouhaha about stopping IRAN or NORTH KOREA from 'developing nuclear power' ends with the 'evil' and 'untrustworthy' pariah state saying:
"Okay, so we won't build the damn thing. In fact, we've destroyed all of our data and designs enabling us or anyone to ever build it.
And Oh, and by the way ... it was a perfectly functional FUSION REACTOR." What?

2old2pb said:

I was thinking about the problems with fusion power when I thought about how stars do it. Big mass of hydrogen collapses under gravity until it's hot enough to fuse. It seems as small as it can go is about 75x the mass of Jupiter to start.

Well I was wondering about a ship made of rings that would magnetically compress the gas until it fuses. How big would it have to be? How close to the artificial star surface would the rings have to be? How would it start up, would it have to be 'fed' hydrogen as it starts up?

The basic idea is the mini-star is the power source, the propulsion and the weapon for the ship. In my still forming story, it's the trump card for failed invasions. The final solution, planet demolishment.

Have fun.......

Click to expand...

That's pretty much how Tokamak reactors work now. The size of the reactor would depend on a lot of constraints that you haven't listed, like the maximum magnetic field the reactor could generate, and maximum desired thrust.

Larry Niven made the point in several of his books that a fusion-drive ship is one hell of a weapon.

But if you mean a weapon as in a "bomb" (as opposed to a fusion-flame blowtorch) an exploding starship probably wouldn't be as efficient as a thermonuclear device designed specifically for that purpose.

I agree with Ted. My main point on that is that ships would be designed to contain and channel that energy - while bombs are made to direct and release then energy.

You'd have to change a lot. I'm not saying it couldn't blow up, I'm just agreeing that given the same materials, a ship would create significantly less firepower than just building a bomb.

Now, I think you could probably set the ship up as a catalyst. I love things like that... taking advantage of a potentially hazardous situation by introducing lots of energy...that could work.

As for size, no idea. I think you could argue that it doesn't have to be too big...our nuclear power plants are pretty small compared to a star, and they contain the energy.

People do suspend a certain amount of disbelief. If a civilization can have a fusion powered ship, why wouldn't they have discovered how to make it small?

The other thing ('cuz I'm such a party poop) is that bombs are a LOT cheaper, relatively speaking, than ships.

A ship has to have all kinds of systems that are unnecessary for a bomb: life support, navigation, communications, steering, computers....

It would make a lot more sense economically to give up on building just one or two ships, and instead build hundreds of hydrogen bombs, planted in strategic locations, ready to blow.

Wikipedia makes so many things so easy...
This is a useful, fairly thorough entry on spaceship propulsion, both current and future. Required reading for all of us space-desk jockeys.

Check out the "fusion rocket" entry.

Hope this is helpful.