Trans-Planetary Subway Systems (1978)

Re:Trans-Planetary Subway Systems (1978) by aidenn0 on Sunday April 11, 2021 @12:44PM (#26771649)

Musk's hyperloop was neither maglev, [edit it actually was an evacuated tube; just not maglev] nor in an evacuated tube. It was an air bearing in a reduced (but still fairly high) pressure tube.

Apparently the air bearing didn't work out, so all the things calling themselves "hyperloop" are maglev and, once you don't need the air bearing, it makes sense to lower the pressure as much as possible.

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Re:Trans-Planetary Subway Systems (1978) by qayxc on Sunday April 11, 2021 @02:50PM (#26772499)

> It was an air bearing in a reduced (but still fairly high) pressure tube.

You are a funny guy :) According to the source [0], the pressure was intended to be 100 Pa ("about 1/6 the pressure of the atmosphere of Mars").

Technically speaking, this is a fairly good medium vacuum [1].

The term "vacuum" itself refers to "a space from which most of the air or gas has been removed" [2], so you don't have to go into the intergalactic void to achieve it. I think ~99.9% qualifies as "most" :D

[0] https://www.tesla.com/sites/default/files/blog_images/hyperl... pg. 12

[1] https://en.wikipedia.org/wiki/Vacuum

[2] https://dictionary.cambridge.org/dictionary/english/vacuum

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Re:Trans-Planetary Subway Systems (1978) by aidenn0 on Sunday April 11, 2021 @03:22PM (#26772726)

Thanks for the correction. I misremembered it as 1/6 the pressure of Earth's atmosphere which is obviously wrong. Yes 100Pa qualifies as "evacuated" by most reasonable definitions.

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