Musk shows hyperloop transport design for people to cars

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An image released by Tesla Motors, is a sketch of the Hyperloop capsule with passengers onboard.

The Hyperloop is here, in its full, theoretical glory.

After keeping the public in suspense for about a year, Elon Musk, the chief executive officer of Tesla Motors Inc. and Space Exploration Technologies Corp., has revealed some concrete details of what he sees as a new, superfast mode of solar-powered transportation.

In typical Musk fashion, the Hyperloop stands as a challenge to the status quo -- in this case, California's $70 billion high-speed train that has been criticized by Musk and others as too expensive, too slow and too impractical.

As Musk envisions it, the Hyperloop would transport people from city to city via pods enclosed inside of tubes, Bloomberg reported yesterday on its website. He describes the design as looking like a double-barreled shotgun with the tubes running side-by-side for most of the journey and closing the loop at either end.

These tubes would be mounted on columns 50 to 100 yards (45.7 to 91.4 meters) apart with the pods inside of them going as fast as 800 miles (1,300 kilometers) per hour -- fast enough to move someone from Los Angeles to San Francisco in 30 minutes.

While Musk had hinted at some of these specifications before, he now provides the twist that the pods could ferry people and their cars, too.

"I think to make it really awesome you want the pod to take cars as well as people," Musk said in an interview before the Hyperloop design was revealed. "You just drive on, and the pod departs."

Musk posted a blog entry yesterday giving details on the Hyperloop concept, followed by a conference call with reporters.

Musk's career

Most of Musk's entrepreneurial career has been spent attacking businesses that he deems inefficient or uninspiring. He co-founded PayPal in a bid to shake up the banking industry and then used the fortune he made selling the startup to EBay Inc. to fund equally ambitious efforts in transportation.

Tesla, for example, has built the highest performing, highest rated mainstream all-electric car and a complementary network of charging stations scattered around North America. Meanwhile, SpaceX competes against entire nations in the market to send up satellites and resupply the International Space Station.

In the case of the Hyperloop, Musk's creative juices began flowing after he grew disenchanted with California's coming high-speed rail system. Construction on a small section of the train is meant to begin in earnest this year. By 2029, some 800 miles of track should link cities from San Diego to Sacramento at speeds of more than 200 miles per hour. The train, which has endured much political wrangling, has been budgeted at about $70 billion.

"˜Final costs'

"You have to look at what they say it will cost versus the actual final costs, and I think it's safe to say you're talking about a $100 billion-plus train," Musk said, while also knocking the train as slow and a horrendous land rights mess.

By placing the Hyperloop on elevated columns, Musk thinks he could avoid many of the land issues. The tubes would, for the most part, follow Interstate 5, the dreary but direct freeway between Los Angeles and points near San Francisco. Farmers would not have swaths of their land blocked by train tracks but could instead access their land between the columns. Musk figures the Hyperloop could be built for $6 billion with people-only pods, or for $10 billion with the larger pods capable of holding cars. So in effect, he's proposing an alternative that's four times as fast and 1/10 the cost of the high-speed rail.

"˜Much cheaper'

The Hyperloop would be solar powered and tickets would be "much cheaper" than those for a plane ride, said Musk. "There would be solar panels laid on top of the tubes, which generate energy for moving the pods and for excess energy that would be stored, so it can run at night," he said.

As for safety? Musk has heard of it.

"There's an emergency brake," he said. "Generally, though, the safe distance between the pods would be about 5 miles, so you could have about 70 pods between Los Angeles and San Francisco that leave every 30 seconds. It's like getting a ride on Space Mountain at Disneyland."

The Hyperloop was designed to link cities less than 1,000 miles apart that have high amounts of traffic between them, Musk said. Less than 1,000 miles, the Hyperloop has a nice edge over planes, which need a lot of time to take off and land.

"It makes sense for things like L.A. to San Francisco, New York to D.C., New York to Boston and that sort of thing," Musk said. "Over 1,000 miles, the tube cost starts to become prohibitive, and you don't want tubes every which way. You don't want to live in Tube Land."

Businessweek interview

Musk discussed the Hyperloop during an interview with Bloomberg Businessweek last year, and plenty of people have spent the subsequent months speculating about how it might look. Critics, dealing with limited information, have contended that the specifications laid out by Musk would be near-impossible to achieve. Such a long, pressurized tube would require an immense amount of energy, while also producing tons of air friction and heat.

In response, Musk argues that the Hyperloop represents a type of middle ground that other people have yet to consider: Instead of being a complete vacuum, the Hyperloop tubes would be under low pressure.

"I think a lot of people tended to gravitate to one idea or the other as opposed to thinking about lower pressure," Musk said. "I have never seen that idea anywhere."

The pods inside of the tubes would be mounted on thin skis that shoot air out of tiny holes at their base like those on an air-hockey table.

"˜Little holes'

"The air gets pumped through little holes and makes like an air cushion," Musk said. The front of the pod would have a pair of air jet inlets -- sort of like the Concorde. An electric turbo compressor would take the air from the nose, compress it and route it to the skis and to the cabin. About a dozen people at Tesla and SpaceX have helped Musk with the design and checked the physics behind the Hyperloop.

There would also be a thin row of magnets on the skis. These would be used to give the pod its initial thrust via a linear electric motor that would produce an electromagnetic pulse that that travels along the tube and pushes it to that initial velocity of 800 mph. Such technology has been used with maglev trains and roller coasters to impart a strong initial force that can get an object going quickly in one direction.

"When you arrive at your destination, another motor absorbs your kinetic energy and puts it into a battery pack, which is then used to provide the source energy for accelerating the next pod," Musk said.

Tube temperature

The temperature inside of the tubes would be between 70 and 80 degrees Fahrenheit. Higher temperatures increase the speed of sound from a baseline of 768 mph at sea level, which means the pods could travel at 800 miles per hour without creating a sonic boom. Also, Musk sees this design producing tailwinds on the pods of 200 to 300 mph, which increases their speed relative to the ground but not the Mach speed or speed relative to the sound barrier.

"The pod can go just below the speed of sound relative to the air," Musk says.

Martin Simon, a professor of physics at UCLA, briefed on some of the Hyperloop details, said it seems feasible from a technological standpoint.

"It does sound like it's all done with known technology," Simon said. "It's not like he's counting on something brand new to be invented."

"˜Air cushion'

Simon said that the acceleration methods proposed by Musk are used at amusement parks to get a roller coaster going. Other companies have looked at these techniques for passenger and freight vehicles. What sets the Hyperloop apart is the use of the air cushion to levitate the pods.

"He has separated the air cushion and the linear induction drive, and that seems new," Simon said, adding that, "It would be cool if they had transparent tubes."

During yesterday's conference call, Musk said that he's leaning toward building a prototype of the Hyperloop to prove that it can be done.

"I have come around on my thinking a bit here," he said. Earlier, Musk said he preferred that someone else develop the technology.

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