Yeah, not a vac tube: https://twitter.com/elonmusk/status/224406502188916739 https://twitter.com/elonmusk/status/224406502188916739 Think "cheap". The cheapest

Yeah, not a vac tube: https://twitter.com/elonmusk/status/224406502188916739 https://twitter.com/elonmusk/status/224406502188916739 Think "cheap". The cheapest vacuum is right above us: at 35 km up there's only 1% the air pressure at the surface. It takes some energy to get there, but if you're on a rail you can recoup it on the way down.