Last weekend, dozens of teams gathered at Texas A&M to present their pod designs for a Hyperloop—a new form of transit that will hurdle riders across land at 700 mph using pressurized tubes, as envisioned by Elon Musk in 2013. The event, at least from afar, looked kind of like the engineering world's Coachella: One attendee snapped a picture of event swag, a white sock printed with the words "World’s First Hyperloop Tube (Sock)." Later, there was even a surprise appearance by Musk himself.
The event marked the end of the first half of a competition SpaceX launched in summer 2015, inviting students and engineers from all over the world to present their designs for a Hyperloop pod in Texas. Now, 22 of those teams will advance to the final round, culminating in a real-life test of their pod designs on a test track SpaceX is building this coming summer.
Out of those who made the cut, two were singled out for their designs: MIT, which won the overall honors, and Delft University in the Netherlands, which won honors for innovation. Their designs give us a glimpse at how the idea of the Hyperloop is evolving—and show how many fundamental aspects of its design are still up for debate, even by Musk himself.
Take MIT’s pod, created by grad students who compare it to a bobsled. The carbon fiber and polycarbonate pods will each weigh about 550 pounds and levitate a half inch above an aluminum plate embedded in the test track thanks to neodymium magnets. Popular Science, which was on the ground at the event, has more:
MIT elected to use an external propulsion system that will function more or less like the catapults used by aircraft carriers to launch aircraft from the middle of the ocean. This feature will offload some of the energy and power required by the Hyperloop concept onto the propulsion system, which means the pod doesn't have to carry an engine and can be lighter (and reach ultra-high speeds).
The system will be autonomous and power itself thanks to photovoltaic panels tiled on the top of the steel tube. "It's more akin to a high-altitude aircraft," says grad student Max Opgenoord in a video. "Which is not something people design for very often. That means there’s not a whole lot of information out there on it. So we've had to do a lot of it ourselves."
Meanwhile, in a video of their presentation, Delft's students got much more specific about the interior design and user experience of their pod. Similar to MIT, they're using a magnetic suspension system that would levitate the pod over an aluminum sheet in the track when it speeds up (both proposals include a secondary set of normal wheels for slower speeds). Their proposal also uses another set of magnets to stabilize the pod over the center beam of the track and act like emergency brakes, a major factor in SpaceX's judging criteria.
The pod itself is as nimble as possible; the designers say it's three times lighter than the weight of the passengers and luggage inside. This careful balancing act between weight (which increases the motors needed to propel the pods) and pod structure (which must withstand the physics of the tube) is played out in the pod's structural engineering; it's why the doors on the pod are staggered to arrange these points of weakness evenly across the entire body of the pod.
Inside, riders will sit side by side in a narrow berth, augmented by "virtual windows" that show video of the view outside the pod, since the physics of the Hyperloop make windows out of the question. Riders will have control over the lighting, the temperature, and an infotainment system, all from their "luxurious" chairs—all part of what the team calls "the Hyperloop experience."
"It's Important To Limit The Number Of Miracles"
If you followed Elon Musk's original release of the Hyperloop concept, you'll notice that both of these winning designs diverge from his original idea. In 2013, Musk's whitepaper suggested that the pods would use air bearings—rather than magnetic levitation, which would be "prohibitively" expensive—to float inside the tube. Since then, there's been debate about whether air bearings or maglev is the best solution. At the competition last weekend, one student even asked Musk about the controversy—and Musk countered that the best design will depend on the context of the track itself, suggesting that a third option, wheels, might even work in some situations.
"The fundamental economics and physics should drive the true solution," he said. "And I’m not sure we know what that is, yet. That’s what we’re doing here."
All of these unknowns reveal the greater experiment behind the Hyperloop, greater even than a steel tube that shoots tin cans across the surface of the Earth: the way it's being developed. Opening up the basics of the design to thousands of engineers, and even competitors, is a relatively untested way of developing a paradigmatic technology. As he talked about the unknowns last weekend on stage, Musk related it back to his past and future ventures:
If you’re trying to create a company, it’s important to limit the number of miracles in series. So you want to start of with something that’s the most doable, and then expand from there. At SpaceX we started out with what we thought was the smallest useful orbital rocket, and it’s a good thing we did that. At the beginning we really didn’t know what we were doing, and the first the rockets didn’t work. If we had tried to do something much bigger and more complicated, we probably would have run out of money and died. And we barely made it as it is. That in general is good advice for people creating companies: start with the minimally useful system. Something you think is still compelling, but leave future technologies for future upgrades.
It's possible that the Hyperloop test track, where MIT and Delft along with 20 other teams will test their prototypes next summer, will end up a weird footnote in history. It's also possible that it will be a stepping stone to technological progress. Either way, it's going to be quite a show.