The world has had a day to digest Tesla and SpaceX CEO Elon Musk's idea of a "hyperloop," a high-speed pod train that would shoot through a tube so rapidly that it could connect Los Angeles and New York in about an hour. And he is mostly being hailed as a visionary, an example of the kind of entrepreneurial, can-do spirit that America needs.
But not all think the idea is feasible, that traveling coast-to-coast faster than a jet aircraft by tube would be really, really difficult.
Sam Jaffe, writing on the Navigant Research blog, says after reading Musk's 57-page proposal that he sees some big hurdles.
"The biggest concern with this plan has to do with temperature. The pod will be compressing air and expelling it downwards and backwards. All that air compression creates an enormous amount of heat, which can damage the pod and its machinery," Jaffe writes.
He notes that Musk proposes that every passenger pod carry a water tank, which would provide a coolant. The water would turn to steam that would be released at stations. But he questions whether a pod would be able to carry enough water to do the job.
Likewise, the pods would be under a lot of stress. If the tube structure were elevated, it could be subject to buffeting by winds.
Musk's idea isn't new. Ever since pneumatic tubes showed up in offices decades ago -- newspapers used them to carry stories to machines where operators spit them out in lead type for the printing presses -- people have dreamed of traveling through the cylinders at high speed.
Jay Yarow, writing for Business Insider, says a similar idea for transporting passengers was hatched 41 years ago by a RAND researcher, R.M. Salter. He called his hyperloop a "Very High Speed Transit System," or VHST. It, too, depended on trains suspended in midair running through tubes. He says it faced technical challenges, but there were no apparent showstoppers. His system would have been airtight, unlike Musk's.
The idea went no where.
Perhaps the biggest impediment to Musk's idea is that he lacks the time to see it through. Having already shown himself to have the courage to stand up to naysayers -- and put his own fortune on the line -- Musk will have to sit back and see if his ideas are advance in the hands of others.