How is it possible to raid without retreat ability?

[Silent Sorrow]

Having just had a battle (my first real one since I bought the game), I'm wondering how it is that--for a game built on emphasizing the strategy in strategy--there can be no retreat option for combat.

It seems to me that one of the common things I might want to do in a game is raid a planet or system--do some damage and get out, fleet mostly intact. But with the way the game is designed, once your ships are in battle they can't retreat. So a raiding mission is zero sum--you either win completely or don't win and consider whatever ships you sent to have gone on a kamikaze mission.

I don't get it.