Thanks! I just finished a 14 month class in Optics, so it's fresh for me. The alternative to putting something into space is much more preferable. No matter how big a ground based scope it is, you still have all of that air mucking up the data coming in and you just can't get as good of data. Space is just so much better, as you know, it is mostly empty of the matter we are trying to look at. Granted, for many EM frequencies, ground based is fine. But a lot of atoms we are trying to look at happen to be present in the air too, messing up the data. Space costs a lot more, but I think there is no comparison in the long run. The dark side of the moon would be a good combo of both advantages though. You could build and also maintain and modify a very very large telescope with out any air or other ground based interference. The flip side is that it would be even more remote than current space based telescopes and therefore more expensive to get things to, like people, air, water, food, and fuel. But, hey, it's the flipping Moon! Like, we have a semi-good reason to go back now! For science!