Make energy sources grounded in reality

[raxo2222]

Cold fusion, dark matter and dark energy sounds like something from Galactic era, not something to be invented in next 100 years.
That is these sound most far out of there.

So I suggest it to renaming into Thorium Fission and Fusion MK-xx power plants.

Also interstellar X should be Interplanetary X in this screenshot - its mission to Mars, and not to Alpha Centauri.

[Balthagor]

There is already a technology for thorium reactor upgrades. The techs you see here are near the top end of the tech tree and have many prerequisites you must pass through to get there. There needs to be something at the high end, and these are what we've created. If you have more suggestions, we're happy to consider them.

[raxo2222]

Fusion - D-T. Earliest fusion reactor, as its easiest reaction to harness. Neutrons are tricky part of problem, on other hand they generate Tritium when colliding with Lithium6 blanket.
Fusion - D-He3. Requires mining on Moon (Helium 3 can be found only on Moon and elsewhere in space).
Fusion - Pure He3. Requires extensive industry in space.
Fusion - CNO cycle. Requires advanced material science, as this reaction is trickiest to sustain. All you need is hydrogen - Carbon, Nitrogen and Oxygen are part of cycle.
All those reactions generate Helium in the end.

Next step would be Antimatter Catalyzed Fusion reactor. You would need antimatter collectors in space.
Most advanced reactor would be Pure Antimatter one - you would need serious space industry to collect solar wind near Mercury, fuse it, use energy to create antimatter, transport antimatter near Earth, and then beam down energy.
That is pure antimatter power plant on Earth can be actually giant energy beam receivers, as energy is beamed from space - we don't want megaton explosion on Earth

You already have Space Race stuff, so you can have those to represent space development without actually creating space related stuff.
Also you can use Space Race thingy to unlock special Ore building - you can have asteroid mining without explicitly creating space assets.
That is in late game you could extract Ore anywhere on Earth.