Indeed, putting the old clues together with his new hints narrows it done quite precisely.
It will be a Ground Effect lifting body on an electromagnetic rail. The lift is provided by aerodynamic effects, and thrust is provided by electromagnetic force.
Based on the details of the design, it would be capable of supersonic speeds like the Concord, while employing Ground Effect like an air hockey table, and propelled like a Rail Gun.
The biggest challenges will be keeping the vehicle stable and at a constant distance from the power rail at high speeds, as aerodynamic disturbances can destabilize the vehicle. Given Elon's expertise with rockets, this should not be too difficult.
Elon's will use electromagnetic propulsion instead of electric fans.
EDIT 2: I just realized this may be Elon's electric jet idea. He may use a ram-air electric jet at high speeds, and only use the power rail to get the vehicle to supersonic speeds where the ram-air engines are most efficient. This would make it MUCH cheaper than maglev by eliminating the power rail on the majority of the track.
Musk has said that his idea of the hyperloop involves a system that "can never crash". Assuming that he's not just talking about really robust safety protocols and instead is referring to some inherent property of the system I think there's probably some missing detail here.
Although I think overall this is probably pretty close.
I believe it will be encapsulated like a dedicated guideway train with walls on both sides so that a de-rail is impossible. The failure mode would likely be the craft slowing down and landing on the track if power is lost.
As a result the vehicle can never crash, but simply lands on the track as it slows down.
I believe Elon is referring to aircraft failure modes when he says "crash", as his Hyperloop vehicle won't drop from an altitude high enough to ever hurt the vehicle or passengers.
EDIT - Response to InclinedPlane's comment below:
The vehicle's angle of attack will be kept almost constant with aerodynamic control systems, similar to a rocket. The reason why NASCAR and F1 cars have spectacular lift crashes is because they are not allowed to have active control surfaces, allowing small aerodynamic perturbations to evolve into massive ones.
The vehicle will likely be kept a few meters off the track to allow for these perturbations. Since the angle of attack is controlled, the only way the lifting body can stall is if it is suddenly immersed in a continuous stream of fully turbulent air. Although extremely unlikely, this is possible, so it can be mitigated with an encapsulated tunnel with fans blowing air in from the outside to gaurantee consistent laminar flow, similar to a wind tunnel.
Maybe, but I'm not convinced. It doesn't matter if you're flying or not, if you're traveling at supersonic speeds and you run into anything, even if you hit the ground from a height of 10cm, it's going to be a bad time. Also, if you're traveling that fast it is magnificently easy to gain a dangerous amount of altitude quickly just by having your vehicle rotate and hit a favorable angle of attack. Just look at how dangerous and dramatic crashes in formula 1 or nascar are, and those vehicles are on the ground, and traveling at maybe 1/5th as fast as a hyperloop vehicle would (and with 1/25th as much kinetic energy).
I'm convinced there either must be some other factor at play or Musk must have worded his statements stronger than is warranted.
Exactly my bet, also if the rail is a tube he gains a way to store electricity in a kind of condenser, has an easy way to keep the "train" stabilized and also isolates the sonic shock from braking half the windows between L.A. And SF. Of course on top of the tube it's easy to install some solar panels.
If the track is not evacuated, what happens to the supersonic shock wave off the nose of the train? Seems to me it would reflect off the ground and enclosing walls, causing all sorts of turbulence.
This is exactly what I'm trying to figure out at the moment. My guess is that the walls will be just far enough to allow the reflections to not disrupt the air immediately surrounding the vehicle, and/or there will be gaps, allowing the shocks to dissipate into the surrounding air.
I assume that a non-evacuated tunnel would require air moving at a speed that is close to (or the same as) that of the train. Keep the air circulating constantly, so it's sealed but not evacuated.
I've thought about it and I believe this is the most likely solution. The vehicle would remain aerodynamically subsonic, but could attain supersonic speeds as the air in the tunnel speeds up. This would also allow vehicles to follow one another without too much separation. Turbo fans can be used to keep the air moving throughout the loop. If enough vehicles are running at full speed, the system will always be "pressurized" as the vehicles themselves will accelerate the air in the loop.
Passenger/cargo loading would occur outside the loop (a fork) and would be brought up to speed by the power rail and inserted into the loop.
I've seen some proposals of building a train in the median of the interestate, a raised track. However, even the interstate isn't straight enough for hypersonic travel in most places, so dunno. I think 'bullet' train speeds in the 200mph realm might be feasible on existing right of ways doing that, but not sure how the hypersonic vehicle would work.
That would be a very cool way to traverse Australia. Do most travelers circumnavigate Australia to get to the other side? I've seen some videos of the "road trains" hauling six trailers across Australia.
A previous HN discussion brought up the possibility of a Launch Loop and several descriptions of that proposal seem to fit very well.
A Launch Loop is an iron cable just 2 inches thick that runs inside of a sheath at tens of thousands of miles an hour. The sheath has electromagnets inside of it to accelerates the cable. The motion of the cable would cause the loop to curve and raise into the sky.
To outside observers, it would look like a giant version of the St. Louis arch with the peak nearly in low earth orbit, but only a few inches thick. The magic comes with the fact that the iron cable can be used for travel by using electromagnetic attraction to the iron cable through the sheath.
What's interesting is that while there are several engineering challenges, unlike a space elevator, this wouldn't require any materials technologies that don't already exist today. The iron cable could be made by existing forges that make the cabling for bridges, and the electromagnetic sheath could borrow a lot of existing technologies from the hard drive manufacturing industry.
It would also fit with his previous work on Space X and Solar Cities to some extent.
A launch loop can be used to transport cargo or passengers high enough that the energy required to get them into orbit is very inexpensive, which ties into his Space X work.
The external sheath of the Launch Loop could have solar panels on it to power the electromagnets that help keep the loop in motion, and even when the sun goes down, millions of tons of iron spinning like a flywheel has enough kinetic energy to keep going until the sun rises again.
I wouldn't be surprised if he ran across the concept when he was researching ways to get into space before he founded Space X, and it's his "Step 2".
Lastly, if you had a giant cable stretched across the sky that worked kind of like a bicycle brake cable in its sheath, but the cable was running through the system at 30k mph in a giant loop, what better name than Hyperloop? It also explains why a trip that he describes as being twice as fast as an airplane would take 30 minutes. It takes more time to go to LEO and back down
Keep an eye out for Musk buying any patents on electromagnetics or him buying a oceanic cable-laying ship.
Musk explicitly mentions, "If you put solar panels on it, you generate more power than you would consume in the system. There's a way to store the power so it would run 24/7 without using batteries." [1]
I think that might be true of launch loops? The cable has incredible kinetic energy, but it is magnetically suspended in a vacuum tube, so its power loss could be low.
Of course, Elon Musk had to throw a wrench in it. From SXSW:
>[The Hyperloop is] not exactly a train. It's a new mode of transportation that doesn't exist. It could be underground or above-ground.
An underground Lofstrom loop seems unlikely.
The most revealing hints are the speed and the cost. Musk says it'll be cheaper than the LA-SF high-speed rail, which is so expensive because the allowable turn radius is enormous. Their right-of-way acquisition is constrained by ruthless physics. Since the allowable radius scales as square of velocity, anything doing LA-SF in 30 minutes will move more or less in a straight line (except near the endpoints).
So it has to be a straight line, but also avoid right-of-way issues. In my mind the Lofstrom loop is still the only option that fits.
Actually, I still think you are right. You know how in pictionary when someone gives an absurd suggestion that is actually not so absurd because you end up mentally responding with 'I guess if you look at it like blah blah..'? I think that's what is going on here.
Musk is thinking, I guess if you put a train in an evacuated tube such that friction was not an issue, and moved it electromagnetically using above ground solar, you could reach supersonic speeds and a lot of the same scientific principles would be shared or be in use. That would fit the idea of a railgun+air hockey+concorde. You could share a lot of the same type of engineers on both projects even though the devices are not related in actuality. He is playing fast and loose interpretation wise and switching between talking about the interface Hyperloop and the particular instantiation he has in mind. It's the only way I can think of where he can claim it's not a vacutrain at the same time as say it could work underground.
But the launch loop fits so much better, in particular because of the massive kinetic energies involved (no batteries for store) and how very well it works with space travel. Even if this particular incarnation doesn't help, it would be invaluable in terms of experience and proof of concept.
Lofstrom has lately been talking about "PowerLoops" - basically underground loops that run for many miles under railroad right-of-ways in order to store energy from windfarms and solar arrays. He seems to indicate that the ROI could be as short as months by buying utility power at night when its cheap and reselling it during the day. Perhaps if the loops were along railroad tracks, they could be used to propel trains? Probably not, but as a power storage method, they can be underground.
http://launchloop.com/PowerLoopAbstract
The people who originated the concept of the launch loop wanted to solve problems of launching spacecraft, thus the name. Elon Musk wants to commute faster between LA and SF, because he does that 400 mile commute 4 times a week. (Obviously Elon also very much wants to launch spacecraft, but maybe has reasons to ignore the launch loop for that purpose.)
With that in mind, is there any reason a launch loop needs to be vertically oriented? Why can't it go, you know, SF, LA, San Diego, Las Vegas, Reno? And if so, why can't parts of it be "underground or above-ground"?
>maybe has reasons to ignore the launch loop for that purpose
True. I think you would probably agree that they're more technical than anti-competitive. Musk has called space elevators a long-term optimization, but points out that you still need rockets anyway. Engineering-wise, a small loop is a lot easier than an orbit-capable loop.
>is there any reason a launch loop needs to be vertically oriented?
In the canonical implementation, the loop is actually fired horizontally from the base stations. The curve ofhe Earth makes the angle for the vertical component.
You're quite right, of course, that the optimized design for launching is different from the optimized design for transport. I picture in my head a >20° departure angle, but I haven't run the math so I really don't know.
I don't quite understand your question. Could you clarify?
Obviously Elon also very much wants to launch spacecraft, but maybe has reasons to ignore the launch loop for that purpose.
Elon wants to be able to launch rockets that can land vertically on Mars.
A spacecraft capable version of a launch loop is a wonderful optimization, but doesn't get him to the rocket technology you need to colonize a planet that does not yet have the technology to build such a launch loop. (Plus he has contracts to fulfill that he can't meet in time with a launch loop.)
Also of interest, the worlds most authoritative subject on Launch Loops is Keith Lofstrom [1]. He maintains a wiki on the subject with amazing information on the concept. [2]
He also maintains a wiki on one of his other projects, Server Sky, a push to get a cloud of micro-satellites in orbit for public access. A literal cloud of servers. [3]
What caught my eye is that Keith Lofstrom spoke at the International Space Development Conference (ISDC) this year and he has a ton of patents under his belt. He's not a kook and seems to really have done his homework on the subject. That makes me think that it's a plausible technology.
What happens to the sonic boom in this scenario? I understand that is the main obstacle to conventional supersonic flights above or close to land, how would this be different?
The tubed is pumped vacuum. See http://launchloop.com/VelocityShear. That also argumentatie that having a heavy fast-moving Core close to a heavy stationery ouder tube is less of a problem than having a hard disk platter close to a stationry 1 gram (possibly less) disk head. I do not quite get that. The damage, once something goes wrong, is way higher, so we should make a much larger effort to decrease the probability that something goes wrong.
That sounds interesting for, say, a sci-fi novel, but in the real world I wouldn't want to be responsible for dealing with infrastructure maintenance, earthquakes, tornadoes... Can you imagine if even part of something like that collapsed?
Over the ocean? Would be relatively minor impact even for a catastrophic failure.
The thing is the speeds - anything that can do NYC-LA in minutes is going to have a catastrophic failure mode that kills everyone in a big radius. I am just trying to imagine the London Underground at 14,000 mph.
I guess the only problem with his is your have to put it 5+ miles out into the ocean and there's really no way you can sail out that far, take the trip and sail back in under 30 minutes.
Elon Musk looks increasingly like someone straight out of Ayn Rand's work. He's the present day Ellis Wyatt or Henry Rearden, tackling grand projects that others shy away from.
He deserves respect just for that — looking beyond the next quarter's bottom line. Just look at the contrast this creates with all the managers whose plans for the next quarter are "let's spend slightly more on marketing".
Elon Musk is the last big industrialist alive, after Jobs passing. If his endeavors succeed he'll be remembered alongside Edison, Franklin, Ford, Jobs etc. It's admirable.
I just don't think it has anything to do with Ayn Rand and her philosophy.
Strangely I just had a discussion about rational thinking and I kind of failed to make a point. Rational thinking is better than irrationality and crazy Bible-thumpers, but you really need to get over that. You need to see past this, you need to pass it by and leave it behind as a neat idea born out of the greatest misconception there ever has been: "I think therefore I am". The reality is - I am, therefore I can think.
> Elon Musk is the last big industrialist alive, after Jobs passing. If his endeavors succeed he'll be remembered alongside Edison, Franklin, Ford, Jobs etc. It's admirable.
I think you don't know enough about the world's industrialists. (And neither do I.) Most of them are less well known than Elon Musk. So just because you don't know them doesn't mean they don't exist. My guess is that China has quite a few people with grand ideas and capabilities.
Industrialists in the developing world are disproportionately not those with grand ideas, but political connections and ties to resource extraction industries.
That's an unfair generalization. There are many industrialists in the developing world who started from scratch [1] and without connections, but managed to build something amazing.
Sure, it's a generalization. There are a lot of self-made entrepreneurs in the developing world. There are also a lot of tycoons getting rich in the oil and gas industries because of cozy relationships with corrupt governments.
The U.S. really was never as bad as many developing countries are today. In the age of the robber barons, the U.S. government didn't do anything to stop them, but wasn't in bed with them the same way as in China or Russia. Remember, a huge portion of China's businesses are still state-owned, and many of the rest have very incestuous ties with the government. Think of the defense sector in the U.S., except far less transparent, far more corrupt, and far more extensive.
well, Ayn Rand modulo all the public money he uses in his ventures (state environmental credits for Tesla, contracts with NASA ... ie. taxpayers money, research grants, etc, etc). Then again Ayn Rand did suck state bottle with medicaire and social security. I'm not saying the projects are not ambitious and amazing. But they would not grow so quickly without the State.
Why shouldn't Ayn Rand take medicare and social security? She paid for those services.
Ayn Rand said that of all the things public funds were ever spent on (outside of judicial and national defense), NASA was the most worthy. She wrote admiringly about NASA, revealing a deep respect for its technology, scientific pursuit, and its Apollo launches. They even specifically invited her to an Apollo launch.
I don't think someone that hated NASA - or supposedly would dislike a private SpaceX - would write: "Apollo 11: A Symbol of Man's Greatness." Clearly since Ayn liked NASA, she would love SpaceX as a step in the right direction over public space exploration.
> Why shouldn't Ayn Rand take medicare and social security?
Because she was against it?
Those things are based in principles. In principle I have the right to state funds for all of my children. Because I am against such subsidies I have decided not to request them, even though the state continues to insist that I should and that it is my right. And even though I pay for other people exercising this right.
For Ayn Rand to rail a life long in many different pamphlets against state run entities only to turn around and to use them when times were a bit tougher seems hypocritical to me.
I'm sure she was also against the government taking her money to fund those programs in the first place, but she didn't have a choice. Why does trying to recover some of that money make her a hypocrite?
Most people pay more into insurance programs than they get out. That's how all forms of insurance works. Sheesh.
Ayn Rand ended up taking government benefits because she had to, not because she was trying to get back what she paid in. That's the key part.
Even if she could afford to take care of herself and was just trying to game the system to get her money back, that's morally pretty suspect, too. Imagine trying to mount the same argument about someone who deliberately crashed their car to "recover some of that money" they had to pay in insurance premiums.
Rand spent her whole life decrying people who are dependent on government assistance as looters and parasites, and then she spent the last few years of her life completely dependent on government assistance without it changing her stated beliefs. If you don't see the hypocrisy there, you're trying awfully hard not to.
She is an illustration that you can lead a successful, productive, non-moochery life and still end up needing government assistance at some point.
Strange as it seems that I would defend Ayn Rand, presumably if she hadn't been forced to pay taxes she would have been contributing to some other form of health insurance that would have taken care of her when needed.
Actually Rand probably paid very little into Medicare which was started in 1965 when Rand was already 60 years old. She probably took out many, many times what little she put in.
Yeah, because all the taxes she paid during some of the highest progressive income tax levels in our history were completely separate from the "lock box" where they kept Medicare money.
Considering there was no lock box of money (we ran a deficit the vast majority of the time she was paying taxes - a world war and a depression will do that), yes... money she paid in income tax before medicare was completely separate from the money used to pay for medicare.
She didn't buy her own insurance. She got sick and in order to avoid bankruptcy and continue living, she got on medicare just like all the "takers" she so famously railed against.
She certainly didn't pay her fair share for the insurance. Heck we don't even know if she paid any taxes during that 5 year period which was after she stopped writing and Objectivism had ebbed quite a bit.
(a) They were financially incentivized to repay early.
(b) They got the sweetheart-deal to end all sweetheart-deals: a gigantic cash infusion structured as a loan with a market-beating interest rate, rather than as equity which would have entitled the government to a share of the upside.
Isn't that a standard deal as far as government loans go? It's nothing compared to the auto industry bailouts, where even the equity taken turned up a loss.
Interesting. So if Tesla did well, they would be able to repay the loans and keep the (more valuable) equity. If they failed, the DOE would have some worthless stock...
Still, compared to the other similar loans offered by the US government, I have to judge the Tesla loans as a success.
They are successful in a sort of spot measurement sort of way. Most of us are happy to see what's become of Tesla. The problem with Tesla as a model for government intervention is that, if the government continued to involve itself in industry this way, it would inevitably lose money for the taxpayers. VCs mentally write off the majority of their portfolio and make their profits on the 1-2 smashing successes, which works because VCs purchase a large share of the upside of the whole portfolio. That model would not work at all if the best the VC got from those 1-2 successes was interest payments.
The missing part of the equation is successful businesses generate taxes, failing ones don't. So, as Tesla grows, it pays more taxes. That's how the government will collect the upside. If Tesla doesn't do as well, the government will also collect the (deferred) upside through stocks. The only way the government can lose is if Tesla goes bankrupt. That way the government can make their profits on all the businesses that don't fail, rather than just 1-2 smashing successes.
There's also the taxes the government collects through suppliers to Tesla, as well as sales taxes generated when consumers purchase electric vehicles, etc, taxes from capital gains and dividends of tesla stock, taxes from salary taxes.
I'm simplifying here because I haven't talked about the opportunity cost of the taxes from a petrol car the consumer didn't buy or the other job employees could have held. In general, however, the government will profit as long as value of taxes from economic growth and other benefits exceed the cost of the loan. And remember, for the government, the cost of the loan isn't for taxpayers to bear, but for all holders of US dollars, which include foreign nations and other non-taxpayers, through temporary inflation; Since the government can always print money to lend, and destroy money when the money is repaid, unless the business fails, in which case every US dollar holding person suffers.
Overdoing it, however, will mean displacing existing investors who are arguably better posed to select winners and negatively affect the economy. What I am saying is some level of government intervention may actually be profitable for taxpayers, even if the investment structure doesn't appear so on the surface.
It's like the "Why do governments invest in loss-making airlines?" The answer of course is to bring more tourists to their country by undercharging plane tickets.
Either I don't understand your comment, or you did not understand mine. I used examples of (fictional) characters portraying impressive industrialists/entrepreneurs. I am not sure why you would call these characters 'kooks'.
Pick another example if you don't like mine — my point does not depend on this particular choice.
I want to archive your comment and bring it up again next time there's a discussion of Rand on HN. Musk is her idea of a businessman-hero (yes, government loans notwithstanding... he doesn't have the luxury of playing in a free market to begin with, energy is already highly regulated and subsidized), not the current crop of Wall Street bankers.
Actually, I didn't intend to discuss Rand. I just wanted to use an example of some characters that she created. I'm surprised people get immediately worked up once Ayn Rand gets mentioned.
A lot of people who read and talk about her works turn in to (or reveal themselves as) babbling idiots, so it's easy to mistakenly associate the babbling idiocy with her. From what I've read, she was much more pragmatic than the angry anti-government types who glom on to objectivism.
Love Rand or hate her, she was one of the few authors that glorified successful people instead of vilifying them. Objectivist principles may not be perfect, but they are a far healthier base for society than "you didn't build that".
Simplistic moralizing is problematic whether it's pro/anti government, corporation, or anything else. I don't know if Ayn Rand's writing is like that since I can't stay awake through all the exposition, but it seems like a lot of simple-minded people love her books.
The "you didn't build it" thing kind of makes my point for me, but I don't want to just call you an idiot and move on since I might be misunderstanding your intent. The speaker had a long, well-presented message with that one line that became a slogan for the more idiotic of anti-government talking heads and their followers, and it's a gross mis-representation of the truth to present it without context [1]:
"There are a lot of wealthy, successful Americans who agree with me – because they want to give something back. They know they didn't – look, if you've been successful, you didn't get there on your own. You didn't get there on your own. I'm always struck by people who think, well, it must be because I was just so smart. There are a lot of smart people out there. It must be because I worked harder than everybody else. Let me tell you something – there are a whole bunch of hardworking people out there. (Applause.)"
"If you were successful, somebody along the line gave you some help. There was a great teacher somewhere in your life. Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges. If you've got a business – you didn't build that. Somebody else made that happen. The Internet didn't get invented on its own. Government research created the Internet so that all the companies could make money off the Internet."
"The point is, is that when we succeed, we succeed because of our individual initiative, but also because we do things together. There are some things, just like fighting fires, we don't do on our own. I mean, imagine if everybody had their own fire service. That would be a hard way to organize fighting fires."
You are of course free to disagree, but at least show the basic respect of not misrepresenting the statement or the people who agree with the overall message. Yes, it sounds a lot like he meant it as he worded it in the heat of the moment--by many accounts, he often goes off-script--but you can't possibly believe he meant it the way it's been taken given the speech that surrounded it.
I think the problem is that most people at least have a reasonably clear idea on what colonising Mars would look like. I doubt that there's two people on Earth who agree on exactly what a todo app should do.
As long as we're guessing, here's my idea. An electrically propelled train in a tube. Instead of evacuating the tunnel you have ducts in the walls that vent the high-pressure air from in front of the train to the low-pressure sides/bottom/rear of the train.
This should reduce the energy wasted trying to push a shockwave through the tunnel, and would use the air pressure to keep the train off the walls. This would fit with his "air-hockey" comment, and wouldn't be an evacuated tunnel - which he said it isn't.
edit: And the "loop" part of the name is because the air ducts are loops the same length as the train. They move the air directly from in front where it's high pressure to the rear where it's low pressure.
My guess: Musk is throwing random keywords at the Internet, then feeding all the speculative ideas generated by smart geeks to his engineering team until they come up with the real product ;-).
After I posted this, I noticed a top level comment with the same idea from an account that's been dead for nearly two years, apparently for posting an Office Space joke:
stiller 3 hours ago | link [dead]
At this rate, Elon can simply wait until somebody comes up with a viable plan and say, "yes, that's what Hyperloop was all along."
Robert Jordan actually joked he did this with his novels. He'd just read fansites to see what was the most plausible explanation for an event and go with it.
I would go one step further and say that the mechanism you describe would also keep the train off the floor (and would possibly be handled by the train, not the tunnel). It seems to me that using electromagnets for propulsion only and not for levitation would drastically reduce costs.
I could only guess at the aerodynamics but I have a feeling you could just give the train a flat bottom and make the end of the train pointed like the intake of a jet engine. At speed it would compress the air and force it between the train and the floor of the tube in a way similar to how an air bearing functions. (Actually all sides, assuming it was rectangular, would work in the same way.)
In thinking afterwards about the many good comments that dpark made in the resulting HN discussion, I convinced myself that while my idea was neat, it was unlikely to be correct. (I did not say so anywhere in the discussion because by the time I had worked this out for myself, the discussion was long over.)
Yeah, there are real problems with an evacuated tunnel - such as the fact that any air leak in its hundreds of miles makes it a non-evacuated tunnel. Do something like this and you've got the best of both worlds.
Elon Musk is making America something I'm proud of again. Or at least trying.
I seem to recall Musk specifically said it's not an evacuated tunnel. However, air leaks aren't a huge problem. You just need them to be slower than the pumps that run to maintain low-pressure; since the flow into the tunnel from leaks will increase as the pressure drops in the tunnel, you will reach an equilibrium at some point. For a really leaky tunnel that might be near 1atm; for a well-sealed tunnel it will be near 0atm; a practical transportation tunnel will balance construction and maintenance costs against the diminishing returns of lower pressures.
Standing on the downtown BART platforms you can't help but think about (and literally feel) the massive amounts of air being pushed around by the trains.
An evacuated tunnel would do wonders for both efficiency and hair styles.
Lets assume it is some kind of maglev in a buried tunnel. How does this effect right-of-way? My understanding is the problem for building even a simple high speed train from LA to SF is principally NIMBYism and the resulting lawsuits . This causes costs to sky rocket as you get delays.
It will depend on the jurisdiction. In Australia, for example, what's under the ground generally belongs to the Crown in right of the particular State or Territory.
In general, however, almost any amount of haggling, land resumption / compulsory purchase and rezoning is cheaper than building tunnels.
We talk about disruptive startups. Bringing the cost of tunnels down by an order of magnitude would be fairly ... seismic.
(Unfortunately, the Earth is restless and heartless).
Keep in mind that America is famously horrible at doing public projects of this sort cost-effectively (e.g. the NYC 2nd ave subway is roughly four times more expensive per mile than similar projects in other countries, including very expensive countries like Japan). There are various reasons for this, but a lot of it seems to be dysfunctional bidding rules etc. that result in few bids and poor methods for choosing the winner.
Other countries manage to do similar projects for vastly lower costs, and it seems pretty likely that an intelligently run private project in the U.S. could also manage to do a good job of keeping costs down. [It's not just labor costs, etc either—total cost per mile is remarkably similar all over the world, both in cheap countries and expensive ones, except in the U.S.]
Limits are above and below ground. The FAA has a limit of 2000ft on structures. Beyond that you'll need to go to the mat to get special dispensation to go higher.
Depends if you have the mineral rights or not. You could argue that digging the tunnel is just a very inefficient way of mining your minerals (if you were a property owner, with mineral rights, wishing to stall the project). If you didn't own the mineral rights, there isn't much you could do if the tunnelers took care not to damage your (above ground) property.
> History has shown that some obvious projects, such as tunneling under the English Channel proposed in the time of Napoleon, can be delayed for centuries because of political pressures
I really don't see why, french empire and united kingdom were such good friends :)
On a side note, I feel very sad to consider we could have a mean to travel the world at cheap cost for four decades, and it still cost a salary and sometime about 24h to go to the other side of the world. With all other things Musk has talked about, it really makes think humanity seriously lags.
He has already said it is not an evacuated tube though he chooses his words very carefully in all the talks I've seen. It comes up in just about every long interview he has done over the past year.
The article makes it seem like politics are the only problem. Another problem is that this would be very very expensive. Magnetic levitation train tracks are already expensive. How much is it going to cost to build a vacuum tunnel with some sort of magnetic propulsion system built into the walls of it, not to mention the supporting infrastructure (vacuum pumps, power distribution, safety exits, maintenance tunnels)? Probably not achievable with the current cost of labor and parts (and all the overbilling happening everywhere).
Then there's the danger. What if an earthquake happens? What if the tunnels leak and air or water seeps in? What if your magnetic stabilization system fails for a fraction of a second and your train floating at 14000MPH grazes against the sides of the tunnel? If an accident happened in one of those tunnels, it could easily kill everyone onboard, and disable the tunnel for months.
It's a really nice and futuristic idea, the kind that would once again make the world a smaller place (commuting from SF to NY for work, anyone?), but it probably won't happen until we can really prove such a thing is safe, and we change from capitalism to an economical model where we build things like this because, you know, they're good for humanity as a whole.
Personally I think a project like this would be good for the American economy, but then so would massive investment in solar power plants. Instead you guys gave fat checks to the banks.
> Hyperloop is a “cross between a Concorde, a railgun and an air hockey table.”
I'm thinking Wing in Ground Effect [1], where small vehicles are launched to supersonic speeds using electromagnetic slings (and perhaps then use their own power to super-cruise to the destination and eventually decelerate). You wouldn't need much infrastructure - the cost would be in the vehicles and launching mechanisms.
It must be inmune to weather and take into account that it will be supersonic at least, so it must be covered. Also Elon is very good at going to the basics of the problem like:
-Cost of installing the system
-pass rights
-cost of raw material
-current state of technology (lots of legacy tech on transportation) and "easy" improvements of Efficiency with improved implementation.
Given that thanks to his actual business he has great knowledge of high speed aerodinamics, electromagnetism electrical propulsion and energy storage..
My bet is towards an elevated light tube (not vacuum) that works as a induction propulsor for the vehicle and condensor battery(you may use solar panels on top to recharge it). Also it insulates the "train-plane" from the weather and the exterior from the sonic shock.
The vehicle will be like a electromagnetic train but just for impulsion and braking, it will use the shock waves and ground effect to hold the weight and stabilization. That way the electromagnetic fields don't need to be generated with expensive systems.
The tube could use high voltage lines right of way and some simple metal towers to hold the actual system.
I don't know if it makes sense but if something like this really can work it will be way cheaper that current high speed trains, vacuum capable tube or spinning megatons of steel at high speed through highly populated areas(a mechanical failure has the capability of wiping entire neighborhoods like a wire lawn mower).
Supposedly, sections of the East Side Access subway project in New York cost upwards of one million dollars per foot. I can't imagine how much a vacuum-sealed tunnel would cost.
The costs of East Side Access is almost entirely due to tunneling deep under one of the most heavily built-up areas on the planet, without disruption to either above-ground or underground activities.
Musk's system, if it works, will cost a bundle on this fact alone. Any corridor that would justify such a high speed system would also be stupidly expensive to build through, both to acquire the rights to, and to construct without completely destroying everything along its path.
I'd rather see something essentially a ramjet-in-a-tube, similar to UW's RAMAC space cannon launcher. Essentially, a long tube filled with correct mixtures of natural gas and oxygen, where a double-cone shaped projectile is accelerated through external (railgun?) means into the breech, and then the compression of gas detonates it right behind the projectile, accelerating it like a ramjet at constant acceleration. For a shuttle, you deaccel by running in reverse from midpoint. It'd be like $100 in natural gas to send 100 people from SF to LA at mach. You'd have to build a low-pressure 1-4m diameter pipeline, totally something we know how to do already for water pipes and natural gas pipelines.
If I had $50mm (or access to that level of capital), I'd probably build one as a LEO satellite launcher. Put 20kg satellites into LEO, full of Ka-band gear, for $100k each, several times a day, 365 days a year. On the side of a mountain in Kenya/Ethiopia/Somalia.
Wouldn't you have to re-fuel the tube each time? Presumably this would cost more than $100... and how would this work in reverse to slow down?
I would think (probably incorrectly, since I know next to nothing about it) that a ram-based system would inherently have combustion primarily behind whatever tightest-seal exists that's bringing the gasses up to combustion temperature, since doing so would also mean the expansion pushes forward against that seal. Or does simply sealing a bit better cause combustion in front of the seal?
Actually I didn't think as much about how to do deacceleration correctly; you wouldn't be able to just flip it around and do ramjet-style, you'd have to use a progressively more sense fluid to fill the tube, which would create a lot of heat. You could still do braking over a hundred miles, progressively, though.
The main goal (vs. a regular cannon) would be to spread the impulse over a long acceleration area, not all at once like with an explosive-powered gun. People would probably be happiest with <1G.
Ok, fair enough. I wasn't taking that sentence very seriously. I suppose he could try to get people to ride it, especially if he only operated out of a country where the regulations were lax enough.
Yeah, it's a little off-the-cuff. They definitely sound more interested in launching satellites (an interesting system for doing so, to be sure). I'm biasing it towards people-oriented since this is all anchored by a hyperloop article.
Yeah, it's really two separate things, but related.
1) Satellite launch using a 1-10km long, 1m diameter tube on the side of a mountain in Somalia. Conventional RAMAC. Small impulse, long push from natural gas ramjet in the tube, potentially an atmospheric rocket stage, and a circularizing rocket (probably liquid fueled, using liquid fuel to fill the void spaces around deployables to deal with the 1000-5000G acceleration). This is just a matter of financing and implementation, I think -- the basic engineering and science is pretty sound.
I think this could actually be <10G, and thus suitable for humans, if you had an 8-9m diameter tube. The peak acceleration goes down with longer/thicker tubes. For a 155mm, it's about 50k G. An iPhone is fine at 5k G; potted boards are fine at 50k G (we have artillery rounds which have satellite receivers, guidance, etc.)
2) A long tube, continuous, designed on the same principle. Mag rail gun to start, natural gas in the tube for ramac (continuous or maybe intermittent), and air bearings, and then either reverse-ramac or just steadily increase density to brake. Doing this for passengers is maybe possible. I'm not sure if the engineering works out at all.
That's why, for satellite launch, it would go in the Horn of Africa. Maximum volume is at the muzzle, and would pretty much require an exclusion zone of maybe 10 miles out, and would be deafeningly loud for another 50 miles. Mountains would be ideal for this.
Elon Musk knows how to keep Tesla and himself in the news.
Tesla is successful so far only because of his strategic marketing. People have build great stuff in the past but not really appreciated because they did not market well.
There is huge learning from this. I personally like his execution.
Don't forget that the car itself got the highest rating ever from one of the most independent reviewing organizations in existence. But, yes, the marketing is pretty terrific, too.
Since we are generally speculating here, is there any possibility the Hyperloop could be a suborbital craft to escape the atmosphere and thus reduce journey times dramatically.
That doesn't really work for "San Francisco to LA" but Richard Branson has mentioned this as an objective for Virgin Galactic "within the next 20 years". I'd be surprised if SpaceX, and hence Elon Musk, were not also looking in to this considering the technology they are creating.
Successfully isolating from earth movements would be my biggest worry about a project like that. The system is going to need a good bit of flexibility built in.
Anyone have any idea why? It seems to me like seismic shifting underground would be many times worse than above-ground, if only because you have to dig to make room (either before or after such shifts).
NORAD and the LHC are examples of successful underground projects that have addressed the seismic issues.
I agree with you that to reach the level of safety consumers will demand, more thought needs to go into it. But it's not impossible, which was kind of in line with what the article was saying.
Note that Japan's Chuo Shinkansen is to be approximately 60% underground (much of that "deep underground").
... and it's real-world, actually-being-built, long-distance (about 300km for the first phase), safety-critical (transports passengers at high-speed), market-financed project in a highly seismically active area.
That's only about half the speed that the hyperloop is being advertised at, though. That route is claiming ~500km/h, which would put you from SF to LA in about an hour, if this site is accurate: http://www.mapcrow.info/Distance_between_Los_Angeles_US_and_...
Which is not to imply that's not an incredible feat - the Shinkansens are awesome, and work. Just that things get harder practically exponentially as you increase speed, so doubling it is a very, very big jump.
Sure, I was just responding to the subthread about the feability of long-distance precise/safety-critical tunnel-construction in seismically active areas.
Nobody knows what hyperloop is anyway (and it's not even clear that Musk actually has a real plan), so it's hard to say much about the details! :]
Are there earthquakes around NORAD (it has long underground tubes?) and the LHC? I really have no idea, and Google is failing me (and it's slow going, very bad internet connection at the moment). And I feel I should point out that the LHC doesn't cross major fault-lines like any trans-USA transportation system would have to do (or even SF to LA, which is explicitly used as an example, and presumably that's much easier than LA to NY (which also crosses the San Andreas fault line)).
Anyway, I'm questioning underground tubes in places where the earth moves at "about 33 to 37 millimeters (1.3 to 1.5 in) a year across California."[1]. While that's not much per year, it adds up, and presumably such a large project would be built to last more than a couple decades (or plan for fairly routine major construction work to keep things straight).
I don't have a structural engineering background so I'm having a tough time imagining how someone could make a train-track or hardened tunnel "flexible" but I'm sure there are many ways.
It doesn't seem too hard to predict the movement of the plates and build in automatic adjustments for the track/tunnel. Have a way to automatically extend track/tunnel and move it laterally to adjust for any minor plate movement.
It seems like it would be cheaper and just as effective to build higher speed rail beside of existing rail lines. Or maybe some sort of independently powered train cars that are private so that there are no unnecessary stops, more automated, and can travel faster. Train tracks likely already have to compensate for the faults somehow, though their probably slightly simpler.
Regenerative breaking would be nifty technology to build into the trains/cars/vehicles and musk has teams with significant experience in these fields.
I imagine that, with all the of top-tier engineers that Musk has on his payroll at tesla, spacex, and solarcity, he can get plenty of suggestions for how to overcome or prevent several feet of movement in the track, humans have done more complicated stuff than that. Then make sure to make redundancy and backup of backups to prevent loss of life and help prevent gridlock in the event of a major disaster (vehicles could go backwards maybe?).
While that article says it will take 21 minutes to travel from LA to NY, Elon explained that the Hyperloop will make you travel from LA to SF in less than 30 minutes. It's a matter of definition, but I believe the Hyperloop is slower.
He also publicy said “It is not an evacuated tunnel”.
Previous discussion: https://news.ycombinator.com/item?id=4815665, https://news.ycombinator.com/item?id=4806059 and https://news.ycombinator.com/item?id=4813416