What is going to protect this from all those meteoroids,asteroids and cosmic rays?
I read about other approaches that make me marvel at mankind's genius. For instance, on the moon you could slowly spin a pool of liquid Mercury to obtain a radio telescope that is basically immune from microimpacts. Not sure how it would work once the mercury freezes solid due to lack of sunlight, but I think it's such a beautiful (but maybe impractical) idea :).
Can't you heat it through induction heating? Vacuum is good isolation, so it won't lose heat too fast. Keeping whole pool above -30 °C probably won't require too much energy.
The idea apparently came from Isaac Newton.
But since there is no atmosphere stopping the small ones on the moon, who also can do damage: this likely will be a problem, because there are a lot of them over time.
So a laser shield might sound science fiction, but will maybe be necessary, for longtime operation?
Or is it possible to build some protective sphere, that does not hinder transmission too much?