Damn you imperial bastards for blowing up one of my ships when I had no idea what was happening!

You can bet I reloaded that save. Is there a way to retreat on my turn if I'm totally outmatched? I couldn't find anything and just kind of got stuck in orbit of one of their planets I stumbled on and got shot to pieces. If not, then I'm just going to stockpile some ships and start researching some heavier weapons.