Back when we last discussed this I believe it was supposed to be setup so that you would need at least three cruisers to take a mining colony and in the exchange they would lose one cruiser. If that's not happening then it's a bug. I have some idea of what might be happening but I'll need to talk with Zark / Tsa and get back to you.

Spart - as for how many licks it takes to get to the center of a 400mu planet you could always send some ships over and find out through empirical evidence.