Note that we've never spent as much money as we've always known would be necessary to achieve useful fusion power, so the oft-repeated idea that it's been surprisingly technologically difficult is not actually justified by the historical track record.

> Typically, outsiders cannot comprehend how the massive expenditures never manage to yield energy. Typically, insiders cannot comprehend how little is being invested in a project that presents such immense technical obstacles and also such potential. A graph commonly passed around among the insiders—an enduring scrap of twentieth-century budgetary ephemera—depicts the 1976 federal plan to build a working thermonuclear reactor. The graph tracks various scenarios for attaining fusion energy. The “maximum” effort, the most expensive up front, with initial spending as high as nine billion dollars a year, was projected to yield a reactor by 1990. The “moderate” effort, with spending never exceeding four billion dollars in a year, would take fifteen more years. The fusion community might be easy to criticize for its many unmet milestones, but for decades the United States has never come close to even the moderate effort. In 1977, when the American fusion budget was at its peak, government investment in the research, adjusted for inflation, was seven hundred million dollars; by 1991, this had fallen by more than half. It is now half a billion, not appreciably more than the Korean budget.

http://www.newyorker.com/magazine/2014/03/03/a-star-in-a-bot...

The chart was produced by Energy Research and Development Administration (ERDA), which was later subsumed into the Department of Energy and presumably represented the expert wisdom at the time. It can be found, in 1976 dollars, as figure 1 here:

http://www.21stcenturysciencetech.com/Articles_2010/Winter_2...

If there's any technology more deserving of a modern-day Manhattan Project...

If you take the amount of money they’re asking for, take the value of inventing fusion power (which is enormous), and then apply a very conservative and pessimistic low probability of success, I’m not sure there’s much that has a higher expected value than investing in fusion power.

In 1976 there was a plan to develop fusion by 2005. However, the funding for it was reduced below the level for which they had projections.

https://www.reddit.com/r/Futurology/comments/5gi9yh/fusion_i...

Funding was reduced from those projections because they were for from a crash project that assumed tokamaks would work really well, much better than it turned out they did.

And in hindsight, even given optimistic plasma assumptions, fusion reactors would have been limited by materials and heat transfer issues. These render any DT-burning reactor problematic, independent of the details of confinement.

Yes, the fundamental idea that $X spent will result in Y scientific knowledge and Z technological advances is managerialist wish-fulfillment. Science and engineering aren't remotely that predictable. We can imagine that we know what we need to discover in order to accomplish something, but the universe likes to laugh at us.

That's true, but when the experts say that it will take $X, and the funding level ends up being $X/100, ths results usually aren't unpredictable.

The talking-point that keeps coming up about fusion spending ignores the context that the planned spending was based on a technology that wouldn't have gotten us practical fusion, anyway.

If that $X had been spent, fusion boosters would be complaining about the debacle of wasting all that money on tokamaks and how that undermined fusion research. And if we spent a newly-calculated $X and, years later, still didn't get fusion, the complaint would be exactly that managerial whinge that we just hadn't shoveled enough money down the hole (or down the right hole).

Interesting to note that “tech X is decades” away is actually a nonsensical statement in itself. If we all agree not to research it, then tech X will never arrive (excepting alien visitation).

Pedantic point but also a reminder to avoid fatalism and that as well as extending R&D times, we can also reduce them (see: Apollo).

If it makes you feel better, it probably isn't anymore. ITER, the reactor in France, isn't set up to be efficient. It is more "Well if we make it bigger it is easier. So let's make it A LOT bigger." There's people trying other ways, but ITER is an effort for "show it is possible" and most people think it is.

That being said, the schedule for first fusion is 2025 and D-T operation in 2035 (just under 20yrs). A lot of competitors think they will be successful (at FIRST fusion, not a generator for public use) before then. It is an interesting race.