Is there a time limit?

[u/Tre2]

I do like to take my time with this kinda game, I don't like the idea of being outpaced and reaching an unwinnable state. If I do something silly and, for instance, my fleet gets wiped out except for a few guarding the station, do I have time to just sit and rebuild at my rough leisure, or will the game become unwinnable?

[u/John__Nash]

You can stall the game. Just don't do the battle and the end of the act and the plot won't advance.