The AI always cheats with SSDs. They are capable of bypassing credit requirements and such to mass build them. And they aren't easily destructible, so you can't widdle them down. Here's how you handle it though: Add Wedge Antilles to every campaign, then make it so Lusankya builds really fast, really cheap. SSD vs SSD generally means you win if you aim all fighters on the SSD.
Yeah, they start with one, but that doesn't explain the second one or how they got it so fast. But I think I solved it simply by putting required space station to level 6.
I agree that they cheat with SSD and Soverigns (ive seen two of each on ONE planet). but I'd rather not fight that fight at all. Simplest plans are usually the best ones, but by far the simplest is kitkun's idea. So, did makng space station requirements level 6 stop the AI from building it?