Given the tremendous capital costs and operating power requirements to maintain the vacuum on such a large system, it will not be as cheap as some expect. Just the first step from LA to SF that he is proposing will be very expensive as the seismic requirements will be as stringent as a nuclear plant at every point on the route. That will not be cheap and the ticket prices will have to reflect that to recover the capital costs and operating costs in a reasonable time.
The analysis of this system had the same flaw as the space elevator — it concentrated on marginal cost, rather than average cost (ignoring the huge capital expense).
But at least he’s thinking BIG again. Also the Kalifornia eco nuts will block him at every step. They HATE big projects.
They HATE big projects.
Not if they involve high-speed choo-choos.
The system won’t let me just say LOL or ROFL, but that was funny.
I don’t know if the word “hate” is accurate. There’s a whole cottage industry around environmental impact statements. You have environmental engineers, environmental lawyers, and a host of others who make their livings by stretching out environmental impact assessments for as long as possible. I think they see large projects as near lifetime employment. Then there are the environmental groups who file endless lawsuits until they receive the proper bribes to go away. While their public rhetoric makes it sound like they hate large projects, in their hearts they probably love them, not for the projects themselves but for the money they bring.
It’s humanity that they hate.
Roddenberry had the sub-shuttle in Genesis II, but this looks to be maybe an order of magnitude faster. Roddenberry’s tube train wasn’t going to be practical until the invention of nuclear-powered tunneling machines. Maybe Musk could work on those.
Somewhere in a boxe o’ files containing relics from my undergraduate days I have a paper on this by the then (mid 1970s) chair of the AeroEng department at RPI: “Underground Transport at Air Transport Speeds”. IIRC his concept correctly, the tunnels essentially followed a suborbital trajectory relative to the Earth’s center of mass. He was thinking very big – intercontinental trips.
This made the (very deep) tunnels pretty much impossible to actually construct, but was enough to get him his PhD.
The relatively short Channel Tunnel cost $21 billion to build, according to some quick Googling. I can’t imagine that our tunneling technology has improved enough to allow cost effective tunneling for thousands of miles. That doesn’t even begin to account for the vacuum issues mentioned above.
While this concept is a staple of many science fiction stories, I don’t see it becoming reality any time soon.
Another problem is that you cannot easily move the stations and routes to compensate for changes in demand due to shifts in population, etc. By comparison, relocating an airline route is almost trivial.
You also cannot move routes for changes in geography, which is a non-trivial concern for a route between SF and LA. At least travelling at hyper speed, it will all be over quickly for those onboard, when the Earth decides to change the route for you. Bonus, the bodies will already be buried.
Not so sure about the bodies. That’s a helluva energy release.
At least one statement in that article is plain wrong: Unlike a plane, “it does not have to squander unrecoverable energy climbing to high altitudes.”
Assuming the descent is in “clean” configuration and speed roughly constant, the energy use of a plane is simply the weight times the flight time, divided by the lift-to-drag ratio at cruise. Extra fuel used to climb is substantially regained while flying the last 150 miles or so descending with the engines idling.
While the running costs of a vacuum tube system would be low, the construction costs would I suspect make it impractical on routes that don’t currently support a 737 or A320 every five minutes.
The aerodynamic and engine efficiency of modern jets (not to mention speed and routing flexibility) is making them very hard to beat. Tickets from Wellington to Auckland or Christchurch are NZ$35 (US$28) on A320s on multiple airlines, and they are making profits at those prices. Terrestrial buses are $10 cheaper, but take ten times as long.
Hell, even a lowly Dash-8 (which only needs a 1000m/3300ft runway) is faster than the fastest train in the world.
I suspect that the running costs of maintaining a vacuum across hundreds (thousands if it goes intercontinental) of miles of tunnels through earthquake country are not going to be particularly low.
I was hoping for a system that was not going to involve the impracticalities of this one – drilling perfectly straight tunnels thousands of miles long.
For the last time.. no it’s not.
[Question about Hyperloop.] You know, it’s funny, it’s kind of a combination of electric and aerospace. [..] But the basic thought behind it is to have something like a cross between a rail gun and a Concorde. I sort of like saying that because some people are going to be scared about that and some people will be like yes, that’s awesome. I’m appealing to the second group. [Maglev in a vacuum tube?] Nice try.
The question at the end there completely rules out this possibility.. why bother writing an article about something that Elon has already said it isn’t. Also, why care about anything anyone says they’ve got a half-baked idea about doing? Wait until they do it.
Glad I’m not the only one that noticed.
I keep envisioning a ballistic monorail, but truly, I haven’t a clue.
Just noodling with other plausibilities steming from ‘rail gun and Concorde’…
I come up with railgun-launched hypersonic sub-orbital shutt capsules or lifting-bodies.
A thousand-mile “straight tube” would be a mammoth (and, basically, prohibitive for today) undertaking.
But something like -10- km is eminently doable. Now what’s the greatest acceleration we’re going to be happy with for civilians? 3g (roller coaster?) I get a decent initial velocity.
Now imagine a larger version. Substitute fins for spindly landing legs. Add wings for large cross-range capabilities during post-ballistic glide. Add windows. Subtract takeoff burn — all onboard fuel used for vertical landing on a simple concrete pad. Vehicle is launched from an electric gun running up the side of (e.g.) Pike’s Peak.
The boring machines we do have mean the actual mountain isn’t crucial. But otherwise yes – that’s what I’m thinking.
I was thinking “Lofstrom Launch Loop” when I saw the title, but that’s less practical than the subshuttle.
Why do scientists and engineers try to make a vacuum system in the worst places when there’s essentially “free vacuum” only 100 miles up? A suborbital system makes vastly more sense than any high-speed rail/vacuum rail/PFM rail system.
Sounds ludicrously expensive. Tunnels aren’t cheap. Let alone vacuum sealed tunnels. You could build high speed rail for a fraction of the price.
The first thing that comes to mind is an EM/Slingatron mashup.
Holy crap! I was just joking about applying bank-drive-thru pneumatic tube technology to mass transit…
Actually used in the first NYC subway system.
New York still has a pneumatic subway (not working).
David E. H. Jones, in one of his Daedalus columns, pointed out that if you could make a breathable hyperdense gas mixture whose specific gravity approximated water (or people) you could pump people through tubes at densities surpassing the Tokyo subway system (Futurama seems to have appropriated this).
Well, for transport in evacuated tubes, moving humans is not a good way to start. The money is in moving things like oil or coal faster and more efficiently using cheaper pipelines.
Most oil flows through pipes at around walking speed. Oil flows through the 48-inch diameter Trans Alaska Pipeline at 2.1 mph. If you put the oil in 1-meter long containers and moved it at mach 6 (about 7000 mph), your containers could be spaced 3.3 km apart and still maintain the existing flow rate. If you get the containers to travel with a 150 meter separation you could cut the pipe diameter down to 10 inches and still meet rate. If you boost the speed further or close up the spacing you could get by with an 8-inch or 6-inch pipe. The cost difference between the two pipe sizes is enormous.
To close up the spacing at such velocities you’d have to do a lot of high speed merging and peeling off at both ends of the run, which of course increases the costs but lowers the cycle rate of each entry/induct operation (where you have to move each “barrel” through an airlock for loading into the evacuated pipeline system. They load, then they merge, and merge, and merge as they accelerate, to close up the gaps for the high speed run.
Once you get such a system up an running, even if its just for several hundred miles, the two points are virtually connected in delivery times and you can ship anything that will fit in one of the containers and survive rapid acceleration and decelerations, such as mail, and do so with lower energy loss than pumping a viscous fluid.
Basically, any non-fragile product whose destination is closer to the exit end of the pipeline than the entrance end, and which can fit inside the shipping container (slightly smaller than the pipe diameter), will probably end up being shipped through your system. Unless the development and installation costs are extremely high, payback on even a moderate length run should come quickly, and if you extend the system across the continent you could make serious inroads into the transport of bulk goods (everything from oil to coal to wheat) to mail and package delivery.
The question is can you successfully get a projectile to travel through a small pipe at those velocities, and find investors to support development.
Oopsie, I said mach 6 was about 7,000 mph. I meant 7,000 fps. That will slightly affect the math, but not to any significant degree given the ballpark nature of the calculations.
Surely, the losses due to viscous friction would be enormous?
You can achieve ~30ish minute transit times from LA to NY with suborbital launches. This would be far cheaper than trying to maintain the vaccum on a thousands km mega-tunnel.
One of the Virgin Galactic people who gave a talk at an AIAA meeting I was at once mentioned a scheme to do ballistic flights between their spaceport and one city in Sweden that wasn’t freaking out about having an exotic aircraft land on their runway. The FAA was nervous about having a NOx oxidizer-fueled vehicle at “their” airports.
I’m not sure that’s true. You have to expend a lot of energy to pump out the pipe, but you only have to do that once, since your projectiles will enter and exit through tight-fitting airlocks.
One of the big advantages to the evacuated tube concept is the relatively unrelated feature that the acceleration and deceleration are being done electromagnetically, so you get to use something like nuclear power for propulsion and can recover 80 or 90% of the projectile’s kinetic energy on the receiving end. If you could electromagnetically launch and recover the suborbital lob, it would be ideal, but we’ll probably have to use conventional rockets for at least part of the flight profile. The amount of rocket fuel required for what is essentially a medium range ballistic missile is pretty large compared to the payload, or compared to that required for a high-bypass turbofan flying the same range subsonic.
In at least one vacuum tune transport concept I’ve seen, the pod docked to ports on the side of the tube for loading and unloading payload. The only volume then to be pumped down for each stop is a small space between the doors.
I don’t think the Hyperloop is underground. Musk also claimed it would be solar powered. Also note that the claimed speed is just short of the speed of sound, another important clue.
Here is my theory: An above ground concrete tube, with room for solar cells on the “roof”. Small diameter, as little as 4 ft, reducing cost and right of way problems. One going north, one south, making it a loop. The tube is evacuated, but not very strongly. At each end is a linear accelerator, 3 g on a capsule up to cruising speed. The capsule kept centered not with fancy and expensive magnets but cold gas jets from the capsule, a little like an “air hockey table”. Air pumped from each station so that the remaining gas partial vacuum moves at the same speed around the “loop” as the capsules. Arriving capsules regenerative breaking provides energy for accelerating capsules, improving energy efficiency. Energy can be “stored” in empty recirculating capsules. All the expensive stuff is at each “end”, with the tube being nothing but smooth concrete. Capsule is just a pressure vessel with gas jets (perhaps from simple pressure tanks?) around the perimeter to center it in the tube.
Probably more capital intensive than Musk thinks, but much, much cheaper than a large diameter, underground, ultra high vacuum hypersonic maglev.
Solar-powered… loop-shaped… intercity…
The Roads Must Roll?
I think Trent is right; it’s not an evacuated underground tube, per Musk’s own comments.
My own guess; an electromagnetic launcher for needle-nosed projectiles, using the air in the tube to achieve the needed clearances to the tube walls (effectively, a wrap-around air hockey table, with the air pressure provided by the projectile’s speed). Ramp it up to a high enough speed for a ballistic trajectory from LA to SF. However, landing might be an issue (there might be complaints if the passengers are always arriving dead and liquified). I think he also said it couldn’t crash, which rules out any variant of my notion.
For a really wild-ass guess, how about a variation of the launch loop?
So what is it? I guess we’ll find out when he tells us.
IMHO, a great system for getting from LA to SF would be what we already have; aircraft. If time is the issue, surely finding a way to cut down on airport boarding times would be easier and cheaper than any 60 billion train (which would be slower than even current air travel).
What exactly is the problem they are trying to solve with the high speed train? It won’t be cheaper than air, plus it will be slower. Airport congestion? Surely building more runways and terminals (or just utilizing outlying airfields) is far cheaper?
What I’d really like to see is faster airports AND faster aircraft.
So $198 million divided 3.4 miles is 58.2 million per mile.
58.2 million times 350 miles is 20.38 billion dollars.
Or if planes are 250 million- 81.5 planes.
Or:
California High-Speed Rail
“The plan estimates final cost at Year-Of-Expenditure (YOE) $68 billion for the Phase 1 project, connecting San Francisco with Los Angeles via Central Valley and Palmdale” https://en.wikipedia.org/wiki/California_High-Speed_Rail
Given the tremendous capital costs and operating power requirements to maintain the vacuum on such a large system, it will not be as cheap as some expect. Just the first step from LA to SF that he is proposing will be very expensive as the seismic requirements will be as stringent as a nuclear plant at every point on the route. That will not be cheap and the ticket prices will have to reflect that to recover the capital costs and operating costs in a reasonable time.
The analysis of this system had the same flaw as the space elevator — it concentrated on marginal cost, rather than average cost (ignoring the huge capital expense).
But at least he’s thinking BIG again. Also the Kalifornia eco nuts will block him at every step. They HATE big projects.
They HATE big projects.
Not if they involve high-speed choo-choos.
The system won’t let me just say LOL or ROFL, but that was funny.
I don’t know if the word “hate” is accurate. There’s a whole cottage industry around environmental impact statements. You have environmental engineers, environmental lawyers, and a host of others who make their livings by stretching out environmental impact assessments for as long as possible. I think they see large projects as near lifetime employment. Then there are the environmental groups who file endless lawsuits until they receive the proper bribes to go away. While their public rhetoric makes it sound like they hate large projects, in their hearts they probably love them, not for the projects themselves but for the money they bring.
It’s humanity that they hate.
Roddenberry had the sub-shuttle in Genesis II, but this looks to be maybe an order of magnitude faster. Roddenberry’s tube train wasn’t going to be practical until the invention of nuclear-powered tunneling machines. Maybe Musk could work on those.
Somewhere in a boxe o’ files containing relics from my undergraduate days I have a paper on this by the then (mid 1970s) chair of the AeroEng department at RPI: “Underground Transport at Air Transport Speeds”. IIRC his concept correctly, the tunnels essentially followed a suborbital trajectory relative to the Earth’s center of mass. He was thinking very big – intercontinental trips.
This made the (very deep) tunnels pretty much impossible to actually construct, but was enough to get him his PhD.
The relatively short Channel Tunnel cost $21 billion to build, according to some quick Googling. I can’t imagine that our tunneling technology has improved enough to allow cost effective tunneling for thousands of miles. That doesn’t even begin to account for the vacuum issues mentioned above.
While this concept is a staple of many science fiction stories, I don’t see it becoming reality any time soon.
Another problem is that you cannot easily move the stations and routes to compensate for changes in demand due to shifts in population, etc. By comparison, relocating an airline route is almost trivial.
You also cannot move routes for changes in geography, which is a non-trivial concern for a route between SF and LA. At least travelling at hyper speed, it will all be over quickly for those onboard, when the Earth decides to change the route for you. Bonus, the bodies will already be buried.
Not so sure about the bodies. That’s a helluva energy release.
At least one statement in that article is plain wrong: Unlike a plane, “it does not have to squander unrecoverable energy climbing to high altitudes.”
Assuming the descent is in “clean” configuration and speed roughly constant, the energy use of a plane is simply the weight times the flight time, divided by the lift-to-drag ratio at cruise. Extra fuel used to climb is substantially regained while flying the last 150 miles or so descending with the engines idling.
While the running costs of a vacuum tube system would be low, the construction costs would I suspect make it impractical on routes that don’t currently support a 737 or A320 every five minutes.
The aerodynamic and engine efficiency of modern jets (not to mention speed and routing flexibility) is making them very hard to beat. Tickets from Wellington to Auckland or Christchurch are NZ$35 (US$28) on A320s on multiple airlines, and they are making profits at those prices. Terrestrial buses are $10 cheaper, but take ten times as long.
Hell, even a lowly Dash-8 (which only needs a 1000m/3300ft runway) is faster than the fastest train in the world.
I suspect that the running costs of maintaining a vacuum across hundreds (thousands if it goes intercontinental) of miles of tunnels through earthquake country are not going to be particularly low.
I was hoping for a system that was not going to involve the impracticalities of this one – drilling perfectly straight tunnels thousands of miles long.
For the last time.. no it’s not.
The question at the end there completely rules out this possibility.. why bother writing an article about something that Elon has already said it isn’t. Also, why care about anything anyone says they’ve got a half-baked idea about doing? Wait until they do it.
Glad I’m not the only one that noticed.
I keep envisioning a ballistic monorail, but truly, I haven’t a clue.
Just noodling with other plausibilities steming from ‘rail gun and Concorde’…
I come up with railgun-launched hypersonic sub-orbital
shuttcapsules or lifting-bodies.A thousand-mile “straight tube” would be a mammoth (and, basically, prohibitive for today) undertaking.
But something like -10- km is eminently doable. Now what’s the greatest acceleration we’re going to be happy with for civilians? 3g (roller coaster?) I get a decent initial velocity.
Look at the SpaceX Grasshopper video.
Now imagine a larger version. Substitute fins for spindly landing legs. Add wings for large cross-range capabilities during post-ballistic glide. Add windows. Subtract takeoff burn — all onboard fuel used for vertical landing on a simple concrete pad. Vehicle is launched from an electric gun running up the side of (e.g.) Pike’s Peak.
Sum: Suborbital, gun-launched ballistic rocket transport à la mode Robert A. Heinlein.
Or… “Hyperloop”?
The boring machines we do have mean the actual mountain isn’t crucial. But otherwise yes – that’s what I’m thinking.
I was thinking “Lofstrom Launch Loop” when I saw the title, but that’s less practical than the subshuttle.
Why do scientists and engineers try to make a vacuum system in the worst places when there’s essentially “free vacuum” only 100 miles up? A suborbital system makes vastly more sense than any high-speed rail/vacuum rail/PFM rail system.
Sounds ludicrously expensive. Tunnels aren’t cheap. Let alone vacuum sealed tunnels. You could build high speed rail for a fraction of the price.
The first thing that comes to mind is an EM/Slingatron mashup.
Holy crap! I was just joking about applying bank-drive-thru pneumatic tube technology to mass transit…
Actually used in the first NYC subway system.
New York still has a pneumatic subway (not working).
David E. H. Jones, in one of his Daedalus columns, pointed out that if you could make a breathable hyperdense gas mixture whose specific gravity approximated water (or people) you could pump people through tubes at densities surpassing the Tokyo subway system (Futurama seems to have appropriated this).
Well, for transport in evacuated tubes, moving humans is not a good way to start. The money is in moving things like oil or coal faster and more efficiently using cheaper pipelines.
Most oil flows through pipes at around walking speed. Oil flows through the 48-inch diameter Trans Alaska Pipeline at 2.1 mph. If you put the oil in 1-meter long containers and moved it at mach 6 (about 7000 mph), your containers could be spaced 3.3 km apart and still maintain the existing flow rate. If you get the containers to travel with a 150 meter separation you could cut the pipe diameter down to 10 inches and still meet rate. If you boost the speed further or close up the spacing you could get by with an 8-inch or 6-inch pipe. The cost difference between the two pipe sizes is enormous.
To close up the spacing at such velocities you’d have to do a lot of high speed merging and peeling off at both ends of the run, which of course increases the costs but lowers the cycle rate of each entry/induct operation (where you have to move each “barrel” through an airlock for loading into the evacuated pipeline system. They load, then they merge, and merge, and merge as they accelerate, to close up the gaps for the high speed run.
Once you get such a system up an running, even if its just for several hundred miles, the two points are virtually connected in delivery times and you can ship anything that will fit in one of the containers and survive rapid acceleration and decelerations, such as mail, and do so with lower energy loss than pumping a viscous fluid.
Basically, any non-fragile product whose destination is closer to the exit end of the pipeline than the entrance end, and which can fit inside the shipping container (slightly smaller than the pipe diameter), will probably end up being shipped through your system. Unless the development and installation costs are extremely high, payback on even a moderate length run should come quickly, and if you extend the system across the continent you could make serious inroads into the transport of bulk goods (everything from oil to coal to wheat) to mail and package delivery.
The question is can you successfully get a projectile to travel through a small pipe at those velocities, and find investors to support development.
Oopsie, I said mach 6 was about 7,000 mph. I meant 7,000 fps. That will slightly affect the math, but not to any significant degree given the ballpark nature of the calculations.
Surely, the losses due to viscous friction would be enormous?
You can achieve ~30ish minute transit times from LA to NY with suborbital launches. This would be far cheaper than trying to maintain the vaccum on a thousands km mega-tunnel.
One of the Virgin Galactic people who gave a talk at an AIAA meeting I was at once mentioned a scheme to do ballistic flights between their spaceport and one city in Sweden that wasn’t freaking out about having an exotic aircraft land on their runway. The FAA was nervous about having a NOx oxidizer-fueled vehicle at “their” airports.
I’m not sure that’s true. You have to expend a lot of energy to pump out the pipe, but you only have to do that once, since your projectiles will enter and exit through tight-fitting airlocks.
One of the big advantages to the evacuated tube concept is the relatively unrelated feature that the acceleration and deceleration are being done electromagnetically, so you get to use something like nuclear power for propulsion and can recover 80 or 90% of the projectile’s kinetic energy on the receiving end. If you could electromagnetically launch and recover the suborbital lob, it would be ideal, but we’ll probably have to use conventional rockets for at least part of the flight profile. The amount of rocket fuel required for what is essentially a medium range ballistic missile is pretty large compared to the payload, or compared to that required for a high-bypass turbofan flying the same range subsonic.
In at least one vacuum tune transport concept I’ve seen, the pod docked to ports on the side of the tube for loading and unloading payload. The only volume then to be pumped down for each stop is a small space between the doors.
I don’t think the Hyperloop is underground. Musk also claimed it would be solar powered. Also note that the claimed speed is just short of the speed of sound, another important clue.
Here is my theory: An above ground concrete tube, with room for solar cells on the “roof”. Small diameter, as little as 4 ft, reducing cost and right of way problems. One going north, one south, making it a loop. The tube is evacuated, but not very strongly. At each end is a linear accelerator, 3 g on a capsule up to cruising speed. The capsule kept centered not with fancy and expensive magnets but cold gas jets from the capsule, a little like an “air hockey table”. Air pumped from each station so that the remaining gas partial vacuum moves at the same speed around the “loop” as the capsules. Arriving capsules regenerative breaking provides energy for accelerating capsules, improving energy efficiency. Energy can be “stored” in empty recirculating capsules. All the expensive stuff is at each “end”, with the tube being nothing but smooth concrete. Capsule is just a pressure vessel with gas jets (perhaps from simple pressure tanks?) around the perimeter to center it in the tube.
Probably more capital intensive than Musk thinks, but much, much cheaper than a large diameter, underground, ultra high vacuum hypersonic maglev.
Solar-powered… loop-shaped… intercity…
The Roads Must Roll?
I think Trent is right; it’s not an evacuated underground tube, per Musk’s own comments.
My own guess; an electromagnetic launcher for needle-nosed projectiles, using the air in the tube to achieve the needed clearances to the tube walls (effectively, a wrap-around air hockey table, with the air pressure provided by the projectile’s speed). Ramp it up to a high enough speed for a ballistic trajectory from LA to SF. However, landing might be an issue (there might be complaints if the passengers are always arriving dead and liquified). I think he also said it couldn’t crash, which rules out any variant of my notion.
For a really wild-ass guess, how about a variation of the launch loop?
So what is it? I guess we’ll find out when he tells us.
IMHO, a great system for getting from LA to SF would be what we already have; aircraft. If time is the issue, surely finding a way to cut down on airport boarding times would be easier and cheaper than any 60 billion train (which would be slower than even current air travel).
What exactly is the problem they are trying to solve with the high speed train? It won’t be cheaper than air, plus it will be slower. Airport congestion? Surely building more runways and terminals (or just utilizing outlying airfields) is far cheaper?
What I’d really like to see is faster airports AND faster aircraft.
“But when construction begins on the $198 million Euclid Creek Tunnel”
“And digging 200 feet below the surface through rock ”
“The 18,000-foot-long, 24-foot-diameter Euclid Creek Tunnel will run”
http://blog.cleveland.com/metro/2011/02/deep_underground_cleveland_tun.html
So $198 million divided 3.4 miles is 58.2 million per mile.
58.2 million times 350 miles is 20.38 billion dollars.
Or if planes are 250 million- 81.5 planes.
Or:
California High-Speed Rail
“The plan estimates final cost at Year-Of-Expenditure (YOE) $68 billion for the Phase 1 project, connecting San Francisco with Los Angeles via Central Valley and Palmdale”
https://en.wikipedia.org/wiki/California_High-Speed_Rail