Date:12 December 2013
Not content with overturning two transportation industries, South African-born entrepreneur Elon Musk, head of the space-launch company SpaceX and electric-car manufacturer Tesla Motors, in August unveiled a super-high speed transit concept that would allow passengers to travel from Los Angeles to San Francisco in 35 minutes. But will it actually run? By Michael Belfiore
The Hyperloop concept is bold: pods with 28 passengers whizzing through a tube at 1 223 km/h, with a price tag of R60 billion – or R620 billion less than the planned California High Speed Rail, which would achieve only 354 km/h. Still, Musk’s idea isn’t as outrageous as it might sound.
Dean Peterson, a retired scientist from Los Alamos National Laboratory, where he worked on a maglev cargo transport concept for the US Navy, says there are challenges that need to be overcome, but he remains optimistic. “With existing technologies, we could potentially build this,” he says. “It isn’t so far-out that it’s beyond being a possibility.”
Here are some of the issues developers would have to face in order to make Musk’s “fifth mode of transportation” a reality.
Maintaining low pressure
The 563 km elevated tube would provide a highly depressurised conduit for passenger pods that accelerate by electromagnetic fields in a manner similar to maglev trains. However, instead of magnetically levitating, each 28-person pod would ski on a thin film of air generated by a compressor at the front of the vehicle. Given the low air pressure and the air-cushion ride, the propulsion system would have to boost the pods only at widely spaced intervals, saving energy and operating costs.
Marcel Jufer of the École Polytechnique Fédérale de Lausanne headed the team working on the Swissmetro, a concept for an underground low-pressure maglev. He cites the much lower tube pressure in the Hyperloop as a potential stumbling block. The Hyperloop’s 0,001 of an atmosphere (a unit of pressure equal to the pressure of the air at sea level), he says, would be difficult and costly to maintain and would complicate any rescue efforts. “The main safety concerns are related to the vacuum,” he says. “How would they evacuate passengers?”
The tube’s stators, or field magnets, and the pods’ aluminium rails, which are magnetically propelled by the stators, would experience significant heating – about 71 degrees Celsius added at each acceleration and braking point, Jufer estimates. Keeping them cool would be especially challenging in the low-pressure environment, since convection would be minimal.
The biggest barriers to the Hyperloop may, in fact, be regulatory and economic. Building a high-profile elevated transport system would surely face resistance from property owners and municipalities along the route who fear having their views ruined. And Musk’s R60 billion cost estimate doesn’t take into account purchasing rights of way through some of the most expensive real estate in the United States.
Many of these issues could be resolved after significant computer modelling, followed by real-world testing. This project would greatly benefit from the investment, not just the endorsement, of an influential visionary. Musk has said he’s considering funding development, perhaps at the SpaceX rocket-testing facility in West Texas. That might be the only way the Hyperloop ever becomes more than a 57-page plan.
How it works
A Propulsion: An electric linear-induction-motor system drives the pods at speeds of up to 1 223 km/h; a magnetic field generated by stators located in the capsules pushes sled-like aluminium slats forwards.
B Pod: Each pod holds 28 passengers. A compressor at the front of the pod takes in air and pushes it out at the bottom to suspend the vehicle on a 0,5 mm to 1,27 mm fi lm of high-pressure air. Compressors in the front also pump air to the back, reducing the air flowing around the pods.
C Tube: Segments are welded together and depressurised to about 0,001 of an atmosphere to reduce resistance and friction of the pods. Power comes from solar panels on the roof.
D Pylons: Approximately 25 000 concrete pillars, each 6 m to 30 m tall, support the tube along the 563 km Los Angeles-San Francisco route.
Thumbnail illustration by Martin Laksman