I'll admit, a lot of the time, you just can't get good enough vacuum on Earth. The best we could do was the nano-torr range, but space is much better. This does

I'll admit, a lot of the time, you just can't get good enough vacuum on Earth. The best we could do was the nano-torr range, but space is much better. This does effect testing somewhat. Also, a lot of the time, it's the 'black swans' that really matter. Fun fact: the Hubble flies butt first, as they experimentally discovered that meteorites will affect the telescope less than flying it lenses first. I can't find the pic right now, but there is a softball sized hole in the computer (butt) section.