Q: When I sacrifice a large red ship, does that mean I can take the “capture” action on any three opponent ships, even if I don’t have the red power available in that system?

A: Yes, if you sacrifice a large red ship, you’ll get 3 capture actions which you can take anywhere. But this doesn’t mean you can just capture any 3 ships. It means that, 3 times, you can choose a ship of yours to confer the capture power onto. Imagine those ships simply become red for a moment. Small ships can still only capture other small ships, but larger ships can capture same size or smaller ships.