Many comments have claimed this, but I disagree. Plasma confinement as science has largely been solved now. Like the Rocket Equation, Computational Fluid Dynamics, and other aspects of Aerospace, we know the parameters of how to do it, and it is simply a matter of searching the space, reducing the parameters, via engineering iteration.

We also knew that landing rockets was possible, and closed-cycle combustion engines were possible, the physics said so, and even had prototypes that could do it, but with SpaceX, it is not the science that's the issue, or even one-off engineering feats, but practical, economical, scalable production.

With Fusion, we've already achieved confinement times and burns that show we can make it work. But making it work in a prototype reactor is a far cry from making it work in a commercial reactor which needs to be run everyday and maintained. ITER's been going for 13 years now, and I don't think they're solving any of the problems that SPARC will solve.

Yes, tokamak prototypes have provided the insight to help nail down the plasma physics, but small scale fusion prototypes have helped to do, with much faster turnaround time than $20+ billion mega projects.

What SPARC is saying is that small is beautiful. That because of scaling of the B-field to the fourth power, if you focus on stronger magnets, you can dramatically reduce both the size and the cost to build your fusion reactors.

That is, if you double the strength of your B-field, you shrink the size of the machine needed by a factor of 4. So clearly, instead of focusing on ITER, you should focus on the economics and scaling of REBCO manufacturing, and increases in magnetic field you can eeek out because they pay huge dividends.

In other words, we are not longer at the Von Braun stage of rockets, or even the Apollo stage, we're at the SpaceX stage of dramatically reducing manufacturing costs and increasing use.

Likewise, I think Fusion is poised to move past the Von Braun stage of "is this possible" to "can we build a real reactor?" As long as people can let go of huge super-projects, and we can get funding for a bunch of innovative startups in the space to try various techniques and designs for engineering small, cheap, and rapidly.

Likewise, for Thorium reactors, we already know Molten Salt Reactors work, we already know the Thorium cycle works, and we even know a commercial plant works, as Germany ran one at one point. There are oodles of startups now vying to build small scale thorium reactors. The role the government could play here is, like with NASA, the DOE, could provide capital to reduce risk, and get some of the more promising ventures off the ground.

Most importantly, they need to be allowed to fail.