Part of the problem is that there's a multiple day reflection time that makes things complicated for sweeping across the sky. It's certainly solvable but with

Part of the problem is that there's a multiple day reflection time that makes things complicated for sweeping across the sky. It's certainly solvable but with a minimum 26-140 hour (100-500 au round trip) lag between firing the laser and then receiving the signal, we'd need to observe each swept area of the sky for a week or two at a time to see the return blip. I'd also then guess that a radar setup instead of visible light might work better, but that's also got resolution issues and would need a gigantic and incredibly sensitive receiver to start picking things up. Space based systems for doing all this would probably work better since they wouldn't have to contend with the rotation of the earth itself, but it'd still be hard.