I don't know the answers to these questions, but what I do know is: 1. Elon Musk has thought about them more than we have. 2. If his initial concept turns out

I don't know the answers to these questions, but what I do know is: 1. Elon Musk has thought about them more than we have. 2. If his initial concept turns out to be incorrect in some way, he will change it until it is workable.