I recall at the time it was first proposed, Elon Musk said 0.1kPa which agrees with another comment stating 1 millibar. At the time, criticism comparing it to t

I recall at the time it was first proposed, Elon Musk said 0.1kPa which agrees with another comment stating 1 millibar. At the time, criticism comparing it to the old vactrain idea was dismissed as "but this tube is not fully evacuated". But it's about the same value that was proposed by vactrain, and is 99.9% evacuated.