[jcranmer]

> It does not use vacuum:

IIRC, the proposed pressure was less than 1 kPa. That would be less than the pressure at the Karman Line, the boundary of space.

[intotheabyss]

The proposed pressure was equivalent to 70k feet altitude, IIRC. So a pressure of about 3.5 kPa.

[nickik]

Many people compare it to scientific vacume chaimers that is why its worth pointing out.