There's not enough satellites to be useful yet, terrestrial astronomy is still possible. They'd need to have ten times the current number to stop it, and that's

There's not enough satellites to be useful yet, terrestrial astronomy is still possible. They'd need to have ten times the current number to stop it, and that's not due to happen for a few years. I reckon if they put their mind to it they could cause enough pollution to make cellphones unusable, maybe even open-air wifi. They're smart, I'm sure they have the technology, they could make the whole EM spectrum so dirty the whole sky would glow.