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SpaceX is cheap due to reuse and commercial of the shelf development compared to mostly military-government development. Tunneling gets cheaper due to <...>? I

SpaceX is cheap due to reuse and commercial of the shelf development compared to mostly military-government development. Tunneling gets cheaper due to <...>? I would be interested. I guess the Swiss would be interested too.

imron 9y ago
Musk talked about it here: https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-d160683921ab https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-... Salient points: "If you just do two things you can get to approximately an order of magnitude improvement, and then go beyond that. The first thing to do is cut the tunnel diameter by 2 times or more. A single road tunnel has to be 26 to 28 feet in diameter to allow for crashes and emergency vehicles and sufficient ventilation for combustion engine cars. But if you shrunk it to 12 feet, what we're attempting, which is plenty for a skate to get through, you drop the diameter by a factor of two and the cross-sectional area by a factor of 4. The tunnel costs scales with the cross-sectional area. That's roughly half an order of magnitude improvement right there. Then, tunneling machines tunnel half time and then stop and the rest of the time is reinforcements for the tunnel walls. If you design the machine to do continuous tunneling and reinforcing, that will give you a factor of two improvement. Combine that, and it's a factor of 8. Also these machines are far from being at their power or thermal limit. I think you can get a factor of two, maybe even four or five on top of that. There’s a fairly straightforward series of steps to get somewhere in excess of an order of magnitude improvement in cost per mile. Our target actually is that we have pet snail named Gary from....Sponge Bob Square Pants. Gary is capable of going 14 times faster than a tunnel boring machine. We want to beat Gary."
- alphaalpha101 9y ago
  They're hardly the first to propose tunnels of that size! Ridiculous. Ever been on the tube? Doing it faster does not mean doing it more cheaply. The cost of going slowly is what, labour? They go slowly because the materials they're tunneling through are incredibly varied.

imron 9y ago

Musk talked about it here: https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-d160683921ab https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-... Salient points: "If you just do two things you can get to approximately an order of magnitude improvement, and then go beyond that. The first thing to do is cut the tunnel diameter by 2 times or more. A single road tunnel has to be 26 to 28 feet in diameter to allow for crashes and emergency vehicles and sufficient ventilation for combustion engine cars. But if you shrunk it to 12 feet, what we're attempting, which is plenty for a skate to get through, you drop the diameter by a factor of two and the cross-sectional area by a factor of 4. The tunnel costs scales with the cross-sectional area. That's roughly half an order of magnitude improvement right there. Then, tunneling machines tunnel half time and then stop and the rest of the time is reinforcements for the tunnel walls. If you design the machine to do continuous tunneling and reinforcing, that will give you a factor of two improvement. Combine that, and it's a factor of 8. Also these machines are far from being at their power or thermal limit. I think you can get a factor of two, maybe even four or five on top of that. There’s a fairly straightforward series of steps to get somewhere in excess of an order of magnitude improvement in cost per mile. Our target actually is that we have pet snail named Gary from....Sponge Bob Square Pants. Gary is capable of going 14 times faster than a tunnel boring machine. We want to beat Gary."

alphaalpha101 9y ago
They're hardly the first to propose tunnels of that size! Ridiculous. Ever been on the tube? Doing it faster does not mean doing it more cheaply. The cost of going slowly is what, labour? They go slowly because the materials they're tunneling through are incredibly varied.