I lived in LA and then SF for a combined total of about 17 years, and now that I'm back in the NY area the Mexican food is just not the same. Does anyone have any good suggestions for burritos? The best burritos I've found are from "Taqueria Los Güeros" in various spots in NJ.
So much so that that one might suspect Hyperloop was almost entirely "borrowed" from this idea, which is probably what OP meant to suggest. To be fair, the description of Planetran does note that the boring itself is the unusually hard part. Maybe Elon saw this at some point, figured the boring part was finally solvable (which explains why he made such a big deal about it), and decided to dust it off.
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.
> 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
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.
> Is there truly a new mode of transport – a fifth mode after planes, trains, cars and boats – that meets those criteria and is practical to implement? Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3.
[...]
> Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working.
> It will require advanced tunnel-boring machines, such as hypersonic projectile spallation, laser beam devices, and the "Subterrene" heated tungsten probe that melts through igneous rocks.
Research even before the 70’s in the 50’s people were looking into nuclear powered boring machines that would use heat from nuclear fission to melt rocks.
I don’t know if this was ever gotten to beyond “cool ideas for the nuclear age” concept art pamphlet phase.
