Hacker News Reader

Comment by ElFitz | Hacker News Reader

> this is still exciting given how anemic advancement in the fusion space has been for 50+ years.

"Nuclear fusion. 30 years away since 1950"

Joking aside. I too am glad to see some progress of any kind, and new (seemingly credible) initiatives being funded and pursued

View on HN

> "Nuclear fusion. 30 years away since 1950"

Those projections usually include the caveat "if properly funded" - https://i.imgur.com/3vYLQmm.png

I’m not sure why this is being downvoted. Reactor studies come out every decade and validate this study every time.

I'm not sure lack of money has been the main issue. ITER is projected to cost $22-$65 bn and still won't be able to produce practical power because the tech isn't up to it. It's only the discovery of REBCO magnets that has made the SPAC design perhaps possible.

Switching ITER to an updated design might be an idea.

Where are you getting that ITER budget range? From what I can tell, it is much closer to $20 billion. That’s for a project that began in the 80s and will finish in 2045. 20 billion over 60 years is a pittance compared to the 15+ TW the world spends on energy.

It was an estimate from the US department of energy https://www.nextbigfuture.com/2018/10/nextbigfuture-said-ite... which ITER dispute.

`"Nuclear fusion. 30 years away since 1950"`

I feel like there should be bonus points for getting this quote to the top of every fusion article posted until there's an existing fusion reactor.

Relevant xkcd: https://m.xkcd.com/678/

Have you seen this? I'd love to find an updated version, but they've been making exponential progress on it since the 70's.

https://i.imgur.com/BN0pz.png

There's a version of this graph about 18 minutes into the Dennis Whyte talk linked in the top comment, though if I understand it it's measuring "power out per pulse" where your graph has "power out per unit power in".

He says progress stalled in 1995 and is not projected to continue until ITER is built, 10 years from now. Then the rest of the talk is actually about an alternative to ITER.

“The year of the nuclear desktop”!

Sounds about the same as generalized AI in time tables

To be fair, we have known how to build a working nuclear fusion power generator (probably with less than 30 years of construction) since the 1950s (see Project Orion); it's just a ridiculously huge construction/engineering project (basically a internal combustion engine powered by thermonuclear bombs).

Blocked by the slowness of the space industry.

Orion was essentially an "external combustion engine". I.e. you have a huge piston that is driven by repeated explosion of nuclear bombs. With a spring mecanism to even out the whallops. And no "engine block" around it.

It did not generate electricity, and given the discrete/pulsed nature of the mecanism, I have a hard time seeing how you would "even out" the output, should you decide (somehow) to attach it to a generator. Let alone imagining how you would transport said electricity back to earth.

Because, don't forget, it was possible to have an external combusion engine because it was in space. Even by 50's standards, the project was judged a non-starter for atmospheric flight, from environmental standards point-of-view.

The project itself was in theory viable for it's original objective (space travel), but highly impractical. It requires massive, robust structures (read 'heavy') that can resist very high impacts. Not a problem once you're into space, but you have to get it into space first. And no-one will let you blow up a couple of scores of nukes in the atmosphere, on a recurring basis. The thought of launching hundreds of nukes into space to a ship built in orbit is not exactly an easy proposition either.

Still, should an extinction-level meteor ever show it's face, it would be useful.

For fun : some original footage of the prototypes in flight (using high explosives) https://www.youtube.com/watch?v=Q8Sv5y6iHUM

Strange. I've read about Orion-type vehicles off-and-on for several decades, and the impression I always had was that the shield would be a hemisphere, or parabolic, rather than shaped like a nosecone.

Am I missing something? How do the lower parallel sides help capture the energy of an explosion below the shield?

I've always understood it to be a plate. That way the vector of the forces is in the direction of travel. A parabolic shape would have to resist sideways forces.

A bit like this:

  https://www.centauri-dreams.org/2016/09/16/project-orion-a-nuclear-bomb-and-rocket-all-in-one/

Reply on news.ycombinator.com