What the hell happened to optimism and trust in science? We used to be able to say "In 10 years there'll be a man on the moon" without having ever launched anyone in space. Now people doubt that in 50 years we will have a marginally better battery technology...
Fusion would be there already if only we had believed in it.
And because all the money is in selfie sharing apps, that’s where a large percentage of the brightest minds go to spend their career (as opposed to something less financially responsible, like nuclear fusion engineering, astronomy, or space flight)
And isn't that a bit of a dig at our astronomers and fusion engineers?
In comparison, the most recent DoD budget (in the USA) has ballooned to three-quarters of a trillion. It's clear we're not interested in the future.
That said, they do a lot of great research and some of it even stays unclassified.
Some of that money involves setting up assembly lines.
You cannot know what it will cost to invent something before it is invented. You cannot know how many deadends you will have to go down before you find one that works. In fact, it may be that the invention depends on knowledge or technology that we don't have, and maybe won't have for many many years.
For example, today fusion researchers are using computers to simulate plasma flows, gain a better understanding of plasma, and design better reactors... something that was not possible in the mid-70s when that chart was created.. and would not be possible to do by hand (as was done in the 70s). Hundreds of billions of dollars have gone into creating computers capable of doing that... where is that in your chart?
And to preempt this line: saying they could buy a supercomputer is not a rebuttal. A Cray-2 was the 2nd fastest computer in the world from 1985-1990 (10-15 years after your chart). It's the equivalent to an ipad 2 (a 2011 32-bit mobile low-power processor). I'm using a computer many times faster than that just to type this post.
The chart is not intended to be definitive proof that we would have had fusion power if we had spent the money (lv's last throwaway line notwithstanding.) No one knows what would have happened. To estimate that, we must use our prior based on how long/expensive other major tech developments have been. That's very different than pretending we know fusion's track record.
Incidentally, NASA is currently spending huge amounts of money on computer simulations for the equipment that will return humans to the moon half a century after they were last there. That doesn't mean those simulations are necessary to get to the Moon, as indeed they weren't possible in 1969.
I am expecting that if China announced a working fusion reaction tomorrow, US would put the funding and have one in only 5-6 years.
If I were a politician in 2019 with the right to sign funding and I see this graph, I cut all funding right away. Here's why:
* based on this graph, a simple extrapolation by only 2 years show the achievement of the commercial reactor in 2005. Where's the commercial reactor 14 years later? We are instead only 6.5 years away before pushing a certain button at ITER, which has some type of significance that's not entirely clear
* at least one point on this graph is "cooked": the JT-60U that appears to cross the breakeven point at some point prior to 2000. Here's what wikipedia [1] says about this:
"During deuterium (D–D fuel) plasma experiments in 1998, plasma conditions were achieved which would have achieved break-even—the point where the power produced by the fusion reactions equals the power supplied to operate the machine—if the D–D fuel were replaced with a 1:1 mix of deuterium and tritium (D–T fuel)."
What's the point of the "figure-of-merit" graph then? It projects when we'll get to breakeven or commercial, only to find there that you need to make another tiny change (i.e. substitute D with T) that will take 30 more years?
The triple product is the correct figure of merit and JT-60U did great there. But it was a plasma experiment and did not have the shielding that is necessary to run it with D-T fuel that produces a lot of neutron during fusion. But we know a lot more about neutron fielding than we know about magnetically confined fusion. Improving the plasma handling and the triple product is much harder than adding shielding.
Look. If you have a graph where you show a certain point called "figure-of-merit" being above a so called break-even point, every layperson in this world will assume that you get more energy out than you put in. If you then say that it's breakeven for a different reaction, they'll either question your sanity, or they'll accuse you of bait-and-switch. If you don't understand why you get your funding cut, you'll think life is unjust or cruel. Other people will nod sympathetically when you'll complain of the unfairness of this world , but secretly they'll disagree with you.
So, here's what Zubrin has to say about nuclear fusion and ITER [1]: "While, driven by international rivalry, the world's national fusion programs did advance forcefully between 1960 and 1990, the decision to consolidate all of them into a unified global effort to build the International Experiment Reactor (ITER) has caused nearly all progress to screech to a halt since the 1990s."
Why did this happen? Could it be because laypeople in charge of funding listened to scientists lobbying for a cool (and expensive) magaproject?
[1] https://www.amazon.com/dp/B07HDSSKHJ/ref=dp-kindle-redirect?...
( * ) in all fairness, you only argued that the figure-of-merit it a good metric, which I don't contest.
I am merely pointing out that fusion did not happen, not because it is inherently difficult or because it is a mirage, but because we did not fund it appropriately.
> where is that in your chart?
Way off the right. Fusion was supposed to have been achieved before Windows 95 was out.
But the scaling of tokamaks turned out to be much less favorable than that scenario assumed, and even if it had been favorable that effort was ignoring engineering considerations like limits on wall power density.
When that scenario was revealed to be a mirage, funding declined. Not sure why anyone would have expected otherwise.
There are fundamental problems in achieving economically viable fusion. Nice and clean reactions that power the sun are way too slow, and need immense volume. Faster reactions produce neutrons and still require temperatures several times higher than inside Sun.
Where economy and safety are not the primary concerns, fusion has long been achieved: in bombs.
If ITER fails, what we will have learned about superconducting magnets manufacturing and high-temperature plasma will surely be useful.
But few great things have been accomplished without the risk of looking foolish, at least at the outset.
The change you're observing is a response to the fact that we've implemented most of the low-hanging fruit. What we're left with are much more difficult problems.