SpaceX founder Elon Musk revealed Friday that, his company’s name notwithstanding, his rockets can do more than just explore space. They could also be the future of travel here on Earth.

Building on an idea he first mused about at last year’s International Astronautical Congress, Musk presented a video at this year’s IAC in Adelaide, Australia, detailing how the company’s next-generation rocket could take passengers anywhere on Earth in less than an hour, with most places reachable in just 25 minutes to a half-hour.

“If you build a ship that’s capable of going to Mars, what if you take that same ship and go from one place to another on Earth?” Musk asked as he set up the video. The idea is an evolution of something Musk briefly considered during his 2016 IAC presentation in Guadalajara, Mexico, in which he suggested SpaceX’s rockets could be used for super-fast cargo delivery between cities.

Never one to go with the conservative option, Musk opted for a much grander proposal by including passengers. Based on the video, the idea is similar to what Musk outlined last year, in which the rockets launch from a floating ferry some miles offshore from the city itself. The rocket would reach a top speed of about 18,000 miles per hour.

“The great thing about going to space is there’s no friction, so once you’re out of the atmosphere it’s smooth as silk,” said Musk, promising no turbulence during the outer space portion of the flight.

How smooth the takeoff and landing would be, however — or indeed how much a 25-minute connection between New York and Shanghai would cost — were left unanswered. Musk did not indicate any timeline for the scheme, or indeed any reason to think a timeline exists at all in any serious sense.

Still, the simple fact the video exists suggests Musk is thinking seriously about what his rockets can do while only barely leaving Earth at all.

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