A guy who lands rocket boosters for reuse has certainly thought through the details of an underground transportation system.
Landing rocket boosters is about a thousand times easier than underground transportation.
Reusable booster tech has existed since the 1960's. It wasn't developed further for two reasons:
a) It's massively wasteful because you have to carry the fuel for the return trip.
b) The boosters need to be refurbished afterwards anyways, which is actually more expensive than building a new rocket. (More ways to screw up and less leeway for economies of scale and standardization.)
As far as I know, Musk hasn't solved these problems and isn't even planning to.
Comments
Landing rocket boosters is about a thousand times easier than underground transportation.
Reusable booster tech has existed since the 1960's. It wasn't developed further for two reasons:
a) It's massively wasteful because you have to carry the fuel for the return trip.
b) The boosters need to be refurbished afterwards anyways, which is actually more expensive than building a new rocket. (More ways to screw up and less leeway for economies of scale and standardization.)
As far as I know, Musk hasn't solved these problems and isn't even planning to.