So when Musk, 42, announced he would be publishing plans for the Hyperloop tomorrow, scientists were sent into a tailspin.
They will have to wait for him to post his "alpha design" on the internet, but he has dropped several hints about its features, including that the system will be powered by solar panels.
Musk will not patent the design and it will be "open source", meaning anyone can modify it, or try to build it.
He has quashed speculation it will be a "vactrain", a concept already being pursued by a company in Colorado. His idea "does involve a tube, but not a vacuum tube", he said, adding: "Not frictionless, but very low friction."
In recent weeks a large part of the mystery appeared to have been solved. A technology enthusiast in Canada called John Gardi published a diagram of how the Hyperloop might work.
Gardi, who describes himself modestly as a "tinkerer", came up with a tunnel 2.7m in diameter, raised above the ground on pylons.
It would form a continuous loop between two points. Giant turbines would blast a stream of air into the tube. The 2m-wide pods, carrying people, would be moved by a rail gun: a tube that uses magnets to accelerate material passing along it.
Gardi called it a modern version of the pneumatic tubes banks and stores used to move money
Musk's intended location for the first Hyperloop is California, between Los Angeles and San Francisco. He believes it could carry passengers between the cities in 30 minutes.
