Hyperloopy

hqdefault (1)

Musk gives a technical briefing on his latest big idea

I recently looked at the hyperloop system proposed by SpaceX founder Elon Musk and highlighted a number of problems with the proposed system, notably its likely very high costs, the technical challenges involved in building it, the barf enduing ride and the safety issues. Recently vlogger Thunderf00t (aka Phil Mason) paid the hyperloop prototype track a visit and I thought it would be interesting to review some of his findings.

Firstly he noted that several of the brackets on the hyperloop system are absent and levelling rubber pads have been used here and there to prop up the brackets that remain. He also got out a thermal imaging camera and noted a temperature variation between the top and bottom of the tube. I suspect these two factors are related. Basically the tube is buckling due to the differential rates of expansion between top and bottom (caused by the sun’s heat and the temperature fluctuations you’d get in California over the course of an average day), which probably explains why they’ve had to remove some brackets and prop up others.

Keeping the tube level would be critical to the full sized system, otherwise it would be impossible to maintain an air tight partial vacuum and this “bowing” effect will spread to the track itself, throwing off the tight tolerances needed to operate the pods safely. There appears to be no shock absorbing, suspension nor seismic isolation, all of which would be necessary to level the tube and operate it safely. Without such measures it would likely be impossible to maintain the sort of speeds talked about by Musk and any energy savings gained operating in a partial vacuum would be cancelled out by the energy spent pumping out the air that leaked in.

43A6FBBB00000578-4830420-_Might_be_possible_to_go_supersonic_in_our_test_Hyperloop_tube_e-a-15_1503939128708

The rustaloop….

Thunderf00t also point to signs of rusting within the tube (which isn’t that old) and a significant dust problem. Given that air contains a certain payload of moisture and dust, pumping large volumes of it in and out of the tube would cause a build up of moisture on the walls (leading to rust) and dust accumulating in the tube. Given that the dust would play havoc with the maglev track and equipment he wants to put in the tube, it would be necessary to control this problem.

There are solutions, most factory clean rooms use advanced filtering systems to remove dust particles from the air and a climate control system to control humidity levels. However such systems are also horrendously expensive (I worked on more than a few such systems during my time in industry and I’d estimate you’re talking about a few thousand per cubic metre of space). Building and maintaining a tube hundreds of miles long to those sort of conditions would not be cheap.

Now the supporters of hyperloop would likely point to the latest competition at the track as “proof” that the naysayers are all wrong. Why one of the prototypes hit a speed of over 200mph! Ya, it was basically a glorified electric car running on a monorail, with a range of only 1km (I’m reminded of the joke from Jeremy Clarkson about how Musk’s original Tesla car could achieve the same sort of speed but had a range of only ten metres because that’s when the plug came out of the wall). It was only a fraction the size of the hyperloop tube (hence the loading it put on the tube would be much smaller than a full sized system). And, as Thunderf00t points out, it can actually run faster outside the tube than inside it.

If you want to run high speed electric cars or buses, why not just create a dedicated lane (with crash barriers either side) down the side of existing motorways exclusively for autonomous electric vehicles. Or how about a monorail (as that’s essentially what Musk’s test track amounts too). Either would be significantly cheaper than hyperloop, require no major leaps forward in technology and would be much more flexible than hyperloop, given that you could now make intermediate stops. And this is kind of my point, there’s other practical ways of achieving the same thing. They might not be as “cool” as hyperloop, but they achieve the same end result and would cost a lot less.

This raises an important question, to what extend is Elon Musk aware of these technical problems and potential show stoppers? It could be he’s aware of these issues, but he’s also aware that the media are basically giving him a free pass with no fact checking of his claims and thus he gets free advertising for the products he’s actually trying to sell (such as his cars) along the way. Or it could be he’s simply deluded and actually believes what he says, that such a system can be built on an insanely tight schedule for a budget that is laughably lower than what most experts estimate (and I’m increasingly of the view those experts are if anything under estimating just how expensive a hyperloop would be).

44DCDCB900000578-4933944-image-a-12_1506701245049

And pondering this question, we must look at another announcement from Elon Musk, the idea of using his as of yet unbuilt and untested Mars rocket for city to city transportation. And he’s also talking of getting to Mars by 2024, which is just insane.

What’s the problem with using rockets for long distance mass transit? Well the fact that they are horrendously expensive and dangerous! It costs tens of millions to get an astronaut up to the ISS. Even if we could cut the costs of space flight down to a fraction of this somehow (which would take some doing, as I’ve discussed in a prior article), say $500,000, is there really a market out there for tens of thousands of people who regularly want to blow that sort of money on a trip from NY to Shanghai?

And there’s the safety issue, again something Elon seems to forget. Even the most reliable rockets in the world (the Atlas V system) blow up or fail catastrophically every 60 launches or so (SpaceX track record is closer to 1 in 20). There are fundamental reasons (again as discussed in my prior article) why such failures happen, you could improve safety yes, but never to the extend where it would be comparable with air travel or even car travel. Are these ultra rich commuters going to be happy with taking a 1:20 to 1:400 roll of the dice of either dying, being badly hurt (a launch abort involves being shot away from the rocket at 15-20g’s which generally means a trip to the hospital even for a fit and healthy astronaut) and/or ending up in the middle of nowhere overnight surrounded by wolves (as happened to one Russian crew when their capsule landed in the wrong place hundreds of miles off course).

And there’s no way authorities are going to let you land or take off with a rocket anywhere near a major metropolitan area. Rocket launch centres are kept away from cities for a reason. One need only look at the Intelsat 708 disaster (where an out of control rocket with a malfunctioning auto destruct system ploughed into a small town near the launch facility) or the Nedelin disaster (where a rocket exploded during fuelling killing hundreds of technicians and visiting dignitaries) for proof of what happens when you build them to close to town’s and cities.

And also, rockets are best launched from equatorial locations, where there aren’t many cities. And one has to consider the re-entry path of any capsule and the safety of those under its flight path, given the consequences of the Colombia accident. So all in all, one is forced to call BS on this proposal.

Which again raises the question, why is Musk proposing this? Again, it could be he knows many so-called science journalists (or in other words people who studied science or engineering in college, realised the course was too hard and switched to journalism or liberal arts instead) will give him a free pass and media attention so he can plug his wares. But sooner or later he’s going to have to deliver and what does he do then?

So while I’m hoping this is indeed Elon just taking advantage of the media, its possible he does genuinely believe his outlandish claims and might well be seriously deluded, perhaps even crazy, a modern day Howard Hughes.

Advertisements

About daryan12

Engineer, expertise: Energy, Sustainablity, Computer Aided Engineering, Renewables technology
This entry was posted in aviation, future, robot car, space, technology, transport and tagged , , , , . Bookmark the permalink.

4 Responses to Hyperloopy

  1. At last – someone notices that space travel is a bit dangerous. I am fascinated with the fact that nobody seems to noticed that, after using solar power for propelling spacecraft, now it is plutonium. So much global joy, that Cassini crashed itself into Saturn. But what if it has crashed into a city on Earth? So much hype over “the benefits to mankind”. Exactly what benefits? And at what risk? And could the money – e
    \specially taxpayers’ money, be spent better in other ways?

  2. jfon says:

    Cassini was launched out over the ocean, so the chances of it landing on a city were vanishingly small. Even if it crashed, the radioactive heat generator was encased in graphite blocks lined with iridium, and embedded in an aeroshell to keep it intact on re-entry, plus the ( non-fissionable ) plutonium 238 was in ceramic form, unlikely to leach or corrode. Solar is not much use past the orbit of Mars, the sunlight is too faint, and even on Mars, rovers like Curiosity have achieved much more than underpowered solar probes.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s