Is TS optimistic or pessimistic?

[Polydamas]

The extravagant fusion power in THS, and especially the use of lunar Helium-3, also strikes me as more "space advocates like it and it gives a reason to have humans and vehicles in space" than cold, rational extrapolation. I don't know any of the science involved, but I don't think that most of the people with opinions on the Internet do either (and the ones who do rarely show it).

On the other hand, solar power is growing very fast right now, and private space is doing better than I would have expected. So we might have a cheap-energy future, just like we might have a low-energy one.