Nothing I suppose. Although I think the risk of damage to your ship is very great. And how many opponents will you be able to take out this way? One, two at the most, if you are VERY lucky. Out of maybe ten races? (depending on how much interest this gets.) Even if you survive you may damage your reactor or engines, which will severly limit your ability to find a suitable planet to colonize.
Plus, there will be a nasty suprise for anybody who tries to loiter around in the starting system too long. But I will let you wait for the game to see that.
Or maybe I'll come up with a way to prevent that outright before the game starts. I'll let you know.
Geo