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Is the Hyperloop transport system a mere pipe dream?

At the beginning of the week, Elon Musk finally unveiled the Hyperloop: A partially evacuated tube, where pods floating on air bearings and accelerated by linear motors will travel between San Francisco and Los Angeles in under 30 minutes, at around 760 mph – just under the speed of sound.

While this sounds exciting, it’s important to bear in mind that the Hyperloop – if this hypothetical mode of transport is ever built – serves a very niche need and will probably have almost zero effect on 99 per cent of the world’s population.

The Hyperloop is, in essence, an air hockey table with pucks (pods) that are accelerated inside a tube using a technique that’s similar to railguns. To reduce air resistance (drag), the air pressure inside the loop is reduced to “1/6 that of the pressure of the atmosphere on Mars,” or just 0.1 per cent of Earth’s atmosphere, using vacuum pumps. This reduces the drag by 1,000 times, which suddenly makes near-speed-of-sound travel viable.

While vacuum pumps are used, and the air is very thin inside the Hyperloop, it’s important to note that this isn’t really a vacuum tube. The pressure in the tube will be 100 Pa (0.75 torr), while a high vacuum usually has an air pressure of 0.1 Pa or less, and one of the best known vacuums – outer space – has an air pressure of around 0.0000000001 Pa.

It is difficult enough to create a high vacuum in a single room, and it would be prohibitively difficult (and expensive) to produce a 700-mile-long vacuum tube.

For more details on the Hyperloop’s construction and operation, read our article from earlier in the week. In short, though, the hypothetical design is fairly sound. It does rely on some concepts that have only been tried at smaller scales, though, and so a large-scale prototype would be required before a Los Angeles to San Francisco link would even be considered.

Best case scenario, if the design really does work, Musk thinks the Hyperloop could be completed in the next seven to ten years, at a cost of around $6 billion (£4 billion) – or 10 per cent of the proposed high-speed rail link between the two cities.

Now, no one’s saying that a faster, cheaper mode of transport between cities is a bad thing – but take a moment to consider just how big or small the impact of an LA-SF Hyperloop would be on the life of Americans. How many commute between the two cities on a daily basis? If you lived in San Francisco, would you vacation in LA, or vice versa? The Hyperloop isn’t going to help anyone get from New Jersey or the outer reaches of Brooklyn to their office in Manhattan. The Hyperloop isn’t going to replace that slow train to their parents’ place; they’re still going to need a car for short trips, and planes for long trips.

In Musk’s own words, the Hyperloop is basically designed to replace airplanes for medium-length city hops – between San Francisco and Los Angeles, for example. He also mentions the possibility of larger pods that can carry cargo along with the passengers. A Hyperloop journey would take about half the time of a plane flight, while consuming just one-twentieth of the energy (planes consume an awful lot of fuel) – and thus a significantly lower ticket price (Musk estimates $20, that’s £13, for a one-way passenger ticket from LA to SF). For business types, this sounds awfully compelling. For everyday worker bees, not so much.

Perhaps I’m missing the point, though. The Hyperloop is so radical – so cheap, so efficient, so fast – that it could fundamentally alter how we live our lives. A network of Hyperloops, if geographically and economically feasible, could act as a strong decentralising force, reversing the trend of urbanisation and people moving from rural areas into towns and cities. If you could be in Manhattan in 30 minutes from almost anywhere in Connecticut, New York state, Pennsylvania, or New Jersey, things would change very rapidly for the citizens of New York City.

Hidden away on page 52 of the Hyperloop proposal [PDF], there’s a very interesting map which shows that Hyperloop branches – to San Diego, Las Vegas, Sacramento, and Fresno – would be possible, but there aren’t many details beyond that.

Even so, we would do well to temper our excitement. The Hyperloop is incredibly hypothetical at the moment. The key innovation – that a pod will suck in air and use on-board, battery-powered compressors to create an air bearing beneath it – is entirely novel and untested. Heck, almost every part of the Hyperloop is novel and untested – except for the air bearings, of course, which have been extensively tested by arcade-goers for decades. Unlike its air hockey table forerunner, though, let’s just hope that Musk doesn’t leave the Hyperloop in his entrepreneurial basement gathering dust.