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I'm not out to analyze the clearly knowledgeable content of this article, but I'd not be surprised if someone wrote something just like it when he (Musk) starte

I'm not out to analyze the clearly knowledgeable content of this article, but I'd not be surprised if someone wrote something just like it when he (Musk) started the whole illogical "make a rocket come back and land" stuff. It's not logical, but I'm giving him the benefit of the doubt. Let him do his thing. Who knows?

greglindahl 7y ago
One odd thing is the claim that it's just as cheap to bore a much larger tunnel. Yet no one is bidding a much larger tunnel boring price anywhere close for either the short Las Vegas tunnel or the much longer Chicago one.
- newyankee 7y ago
  It is not odd i think it is a thinly disguised lie. If it was serious it would've done a point by point rebuttal of Elon's proposals and why he think he can reduce the cost more than 10x for same capacity (capacity is the operative word). At the very least it could've shown cost calculations for these tunnels. If they are as attractive as portrayed we would've had many more of them.
  - Gibbon1 7y ago
    Calculate the diameter of two small tunnels that can carry a lane of traffic vs one that can carry two lanes. Single lane, 12 feet wide, 12 feet tall. Requires a tube 17 feet in diameter. Or 54.3 feet circumference. Two of those is then 108.6 feet. A tube that can carry two lanes, 12X2 = 24 feet. Diameter is 26.8 feet or 84.3 ft circumference.
    - superice 7y ago
      Except that in tunnel boring the circumference is not that relevant, it's the surface area of the cross section of your tunnel. In the first instance that's 113.1 square feet, in the second it's 452.4. Every time the radius doubles, the surface area quadruples. The perfect tunnel transports people horizontally in a very narrow tube.
      - Gibbon1 7y ago
        Your forgetting, I'm talking about either two lanes of traffic in one tunnel or one lane of traffic in two tunnels. First order analysis says there is no saving by using two tunnels instead of one. When you consider 4 one lane tunnels vs one tunnel with four lanes of tunnels, the four tunnel solution is worse.
  - ant6n 7y ago
    A detailed rebuttal of musks boring ideas is clearly not the point of the article. But those articles for exist, for example this one (which includes a citation that cost may scale linearly with diameter): https://pedestrianobservations.com/2017/12/15/elon-musks-ideas-about-transportation-are-boring/ https://pedestrianobservations.com/2017/12/15/elon-musks-ide...
progfix 7y ago
The difference is we are building tunnels for many decades and making them smaller, reusing the ground material are not ground breaking ideas.
- rusticpenn 7y ago
  The ground breaking part is not the tunnel but the vehicles. Its extremely dangerous to use ICE vehicles in long tunnels without complex ventilation schemes. Electric vehicles solve this issue.
  - asjw 7y ago
    Electric cars have tires, that produce a lot of the dangerous micro plastic
    - rusticpenn 7y ago
      Tires seem to be completly another beast. Apparently, most of the pollution from tires are usually stuck to the roads and are washed periodically with water and soap [1]. I am not sure how much tires contribute to air pollution. https://nmbu.brage.unit.no/nmbu-xmlui/bitstream/handle/11250/2612289/MASTEROPPGAVE%20Ninni%20og%20Jon%20Petter%202019.pdf?sequence=1&isAllowed=y https://nmbu.brage.unit.no/nmbu-xmlui/bitstream/handle/11250...
      - peller 7y ago
        Sounds like it's more so water pollution where tires are bad: > Driving is not just an air pollution and climate change problem — turns out, it just might be the largest contributor of microplastics in California coastal waters. [...] Rainfall washes more than 7 trillion pieces of microplastics, much of it tire particles left behind on streets, into San Francisco Bay each year — an amount 300 times greater than what comes from microfibers washing off polyester clothes, microbeads from beauty products and the many other plastics washing down our sinks and sewers. https://www.latimes.com/environment/story/2019-10-02/california-microplastics-ocean-study https://www.latimes.com/environment/story/2019-10-02/califor...
aguyfromnb 7y ago
>when he (Musk) started the whole illogical "make a rocket come back and land" stuff. I'm not sure what you mean by "illogical"; the idea of landing rockets has been around for 50 years. The issue is the technical challenges, and the cost. SpaceX have demonstrated that they have solved many of the technical issues, but haven't demonstrated that it's actually worth reusing rockets. I suspect the same thing is true of digging tunnels. We have the technical ability to do it, but it isn't economically viable.
- theptip 7y ago
  > but haven't demonstrated that it's actually worth reusing rockets. What would demonstrate that it's worth it to you? Aren't their reused rockets significantly cheaper than the competition already? Or is there some catch here?
  - aguyfromnb 7y ago
    >Aren't their reused rockets significantly cheaper than the competition already? Are they? Have they re-used their rockets commercially, outside of testing? I was unaware of that, but I don't follow it very closely. Did they not ditch the idea of re-using the second stage, as it proved too expensive? If so, that demonstrates there's sometimes a gap between targets and reality.
    - activelistener 7y ago
      Layman's opinion here, but of course they'd want to reuse their rockets? Why would throwing away your entire product and having to create again from scratch each time be the ideal? This would be an iterative process. First, figure out how to successfully recoup the rocket. Second, see what issues exist with the integrity of these rockets, and work to fix those. Try reusing. Find more issues, fix those, etc. Eventually/hopefully, profit?
    - areyousure 7y ago
      > Are they? Have they re-used their rockets commercially, outside of testing? I was unaware of that, but I don't follow it very closely. https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_development_program#First-stage_reuse https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_... https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters#Booster_turnaround_time https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_b...

greglindahl 7y ago

One odd thing is the claim that it's just as cheap to bore a much larger tunnel. Yet no one is bidding a much larger tunnel boring price anywhere close for either the short Las Vegas tunnel or the much longer Chicago one.

newyankee 7y ago
It is not odd i think it is a thinly disguised lie. If it was serious it would've done a point by point rebuttal of Elon's proposals and why he think he can reduce the cost more than 10x for same capacity (capacity is the operative word). At the very least it could've shown cost calculations for these tunnels. If they are as attractive as portrayed we would've had many more of them.
- Gibbon1 7y ago
  Calculate the diameter of two small tunnels that can carry a lane of traffic vs one that can carry two lanes. Single lane, 12 feet wide, 12 feet tall. Requires a tube 17 feet in diameter. Or 54.3 feet circumference. Two of those is then 108.6 feet. A tube that can carry two lanes, 12X2 = 24 feet. Diameter is 26.8 feet or 84.3 ft circumference.
  - superice 7y ago
    Except that in tunnel boring the circumference is not that relevant, it's the surface area of the cross section of your tunnel. In the first instance that's 113.1 square feet, in the second it's 452.4. Every time the radius doubles, the surface area quadruples. The perfect tunnel transports people horizontally in a very narrow tube.
    - Gibbon1 7y ago
      Your forgetting, I'm talking about either two lanes of traffic in one tunnel or one lane of traffic in two tunnels. First order analysis says there is no saving by using two tunnels instead of one. When you consider 4 one lane tunnels vs one tunnel with four lanes of tunnels, the four tunnel solution is worse.
- ant6n 7y ago
  A detailed rebuttal of musks boring ideas is clearly not the point of the article. But those articles for exist, for example this one (which includes a citation that cost may scale linearly with diameter): https://pedestrianobservations.com/2017/12/15/elon-musks-ideas-about-transportation-are-boring/ https://pedestrianobservations.com/2017/12/15/elon-musks-ide...

progfix 7y ago

The difference is we are building tunnels for many decades and making them smaller, reusing the ground material are not ground breaking ideas.

rusticpenn 7y ago
The ground breaking part is not the tunnel but the vehicles. Its extremely dangerous to use ICE vehicles in long tunnels without complex ventilation schemes. Electric vehicles solve this issue.
- asjw 7y ago
  Electric cars have tires, that produce a lot of the dangerous micro plastic
  - rusticpenn 7y ago
    Tires seem to be completly another beast. Apparently, most of the pollution from tires are usually stuck to the roads and are washed periodically with water and soap [1]. I am not sure how much tires contribute to air pollution. https://nmbu.brage.unit.no/nmbu-xmlui/bitstream/handle/11250/2612289/MASTEROPPGAVE%20Ninni%20og%20Jon%20Petter%202019.pdf?sequence=1&isAllowed=y https://nmbu.brage.unit.no/nmbu-xmlui/bitstream/handle/11250...
    - peller 7y ago
      Sounds like it's more so water pollution where tires are bad: > Driving is not just an air pollution and climate change problem — turns out, it just might be the largest contributor of microplastics in California coastal waters. [...] Rainfall washes more than 7 trillion pieces of microplastics, much of it tire particles left behind on streets, into San Francisco Bay each year — an amount 300 times greater than what comes from microfibers washing off polyester clothes, microbeads from beauty products and the many other plastics washing down our sinks and sewers. https://www.latimes.com/environment/story/2019-10-02/california-microplastics-ocean-study https://www.latimes.com/environment/story/2019-10-02/califor...

aguyfromnb 7y ago

>when he (Musk) started the whole illogical "make a rocket come back and land" stuff. I'm not sure what you mean by "illogical"; the idea of landing rockets has been around for 50 years. The issue is the technical challenges, and the cost. SpaceX have demonstrated that they have solved many of the technical issues, but haven't demonstrated that it's actually worth reusing rockets. I suspect the same thing is true of digging tunnels. We have the technical ability to do it, but it isn't economically viable.

theptip 7y ago
> but haven't demonstrated that it's actually worth reusing rockets. What would demonstrate that it's worth it to you? Aren't their reused rockets significantly cheaper than the competition already? Or is there some catch here?
- aguyfromnb 7y ago
  >Aren't their reused rockets significantly cheaper than the competition already? Are they? Have they re-used their rockets commercially, outside of testing? I was unaware of that, but I don't follow it very closely. Did they not ditch the idea of re-using the second stage, as it proved too expensive? If so, that demonstrates there's sometimes a gap between targets and reality.
  - activelistener 7y ago
    Layman's opinion here, but of course they'd want to reuse their rockets? Why would throwing away your entire product and having to create again from scratch each time be the ideal? This would be an iterative process. First, figure out how to successfully recoup the rocket. Second, see what issues exist with the integrity of these rockets, and work to fix those. Try reusing. Find more issues, fix those, etc. Eventually/hopefully, profit?
  - areyousure 7y ago
    > Are they? Have they re-used their rockets commercially, outside of testing? I was unaware of that, but I don't follow it very closely. https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_development_program#First-stage_reuse https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_... https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters#Booster_turnaround_time https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_b...