Dominions 3000 (name confirmed!)

[Darkwind]

llamabeast said:
So, would the planets be represented by land, and space by water? Then spaceships could be aquatic. The troop carriers could grant "water breathing" to the units they commanded, hence allowing carrying troops through space. However, the troops would then be present in space combats. The only solution I can think of to this would be to have spaceships vastly superior to troops, so that troops fighting in space would be largely irrelevant (as you'd expect if troops were floating around in spacesuits, although that still doesn't explain why they got out of their transports in the first place)

That was what I was thinking, that troop carriers would be able to bring units into space. Endoperez's idea could work, as well, since either way the carriers would have to be amphibious, but with sailing the problem of a small army of units leaving the carrier to unload their clips (or lasers) against the vastly superior hulls of the enemy spaceships is avoided. It might not help with cross-system expeditions, though.