[pfdietz]

It comes from believing that the chance of fusion reaching something that's useful is very small. If it's sufficiently small, then the expected payoff < the cost of the program, and hence the program is not worth pursuing.

Where you and he differ is in your judgment of how likely fusion programs are to succeed.

I personally don't think ITER is worth pursuing. I'm skeptical about other tokamak efforts as well. Small efforts that might yield more attractive reactors (Zap, Helion) may be worth pursuing, not least because such efforts would be cheaper.

[jatone]

the idea that ignores the fact that tackling hard technological problems actually generates a ton of economic activity and generates solutions to other domains.

magnetic confinement, lasers, material sciences have all advanced because of these projects and had impacts in other markets.

even if the money invested never ends up with an ITER reactor. we've still come out ahead economically.

[pfdietz]

I have no respect for spinoff arguments. They're used when one doesn't have a real argument. If any development effort produces spinoffs, why not focus on an effort that also has a chance at a real direct payoff?

[jatone]

I have no respect for people that ignore them. its been shown empirically again and again to occur.

without the original research, the spinoffs may never occur because the initial capital outlay isn't warranted for the various individual uses.

the fact of the matter is fusion reactors are such a game changer ignoring them because of the chance they might not work is insane. meanwhile all the research into getting them to work generates a ton of economic activity because other smaller markets can take advantage of the technological progress that was made in the attempt.

[pfdietz]

Spinoffs have a long and sorry history in NASA advocacy. The problem is that advocates went from "NASA had some minor role in development of technology X" to "NASA is entirely responsible for technology X". One sees this over and over again, to the point of the claims being outright lies. "NASA gave us integrated circuits" is a great example.

Claims that space spending had a 8:1 (or 24:1, or whatever) payback via spinoffs have typically just assumed the spending has the same macroeconomic payoff of private R&D spending, which demonstrates absolutely nothing.

Without that contribution inflation, one has to somehow show that a particular technology would not exist without the putative spinoff contribution. And that's really difficult to do in most cases. Here, the military has had an interest in high power millimeter wave sources for a variety of reasons.

The argument remains, also, that if spinoffs are an inherent part of research, then it doesn't matter what the research is on, and so you get the highest payoff by funding research that makes sense via direct benefits, as the spinoffs come regardless. You'd need to argue that fusion is somehow better at producing spinoffs than other research. I find that likely; I suspect small scale research is more likely to provide spinoffs, as desktop technologies seem likely to have more applications.

[jatone]

your attempting to dismiss the reality of empirically proven occurrences with hand waving. I have no interest in engaging in such a pointless discussion. NASA, the manhattan project, and other endeavors ALL generated giant economic returns from their outputs.

you can hand wave 'possible alternative realities' all you want but the fact is they triggered those economic returns. spacex would be another (recent) example of a primarily NASA funded endeavor that will generate massive returns in the future and would not exist without said funding.

anyways good luck.

[pfdietz]

The handwaving is on your side. How could it be otherwise? To demonstrate a spinoff effect, you have to show that the technology would not have been developed otherwise. But such contrafactual history is just about impossible to prove. And in technology, it's almost always the case that technologies come about because it's time for them to come about (it's "steam engine time"), not because of one irreplaceable inventor or group.

> the fact is they triggered those economic returns.

Your blind faith in this dogma is touching, but it isn't supported by real evidence. For example, if you examine what actually happened, the NASA role in developing integrated circuits was rather minor.

[pfdietz]

s/likely/unlikely/

[ncmncm]

The fact of the matter is that fusion, if ever achieved, will be entirely irrelevant to any concern of the time. It is discounted not because it might not work, but because it would not be useful even if it did work. There are people who willingly pay 10x for luxury goods, but fusion power would be a commodity competing on price with other commodities, and losing.

Whatever "economic activity" happens around fusion would be overwhelmingly better devoted to building out solar, wind, and storage, to slow the fast developing climate disruption catastrophe.

[jatone]

these are not mutually exclusive choices. we can easily afford to do both. case and point: we currently are doing both.