Tesla's new flying Roadster did exactly what Elon Musk said it would in a post 8 years ago

• Musk described his plans for the Tesla Roadster during a 2019 exchange with YouTuber MKBHD.
• On Thursday, the Roadster did exactly as Musk promised nearly eight years ago, leaping into the air.
• While Musk missed his own deadline by years, the technology on display was just as he described it.

It's been a long time coming.

Almost eight years ago, in January 2019, Elon Musk shared plans on Twitter for Tesla's Roadster to lift off using cold-gas thrusters and ultra-high-pressure air. On Thursday, the much-anticipated Roadster did exactly that.

Musk's 2019 assertion came in response to a user sharing a GIF of the DeLorean from "Back to the Future" hovering in midair.

"The new Roadster will actually do something like this," he wrote. Tech YouTuber Marques Brownlee responded: "The thing is I feel like you’re not joking."

"I'm not," Musk said.

He then described a SpaceX-made cold-gas thruster system that uses high-pressure air stored in a composite pressure vessel.

At a SpaceX test site in Texas on Thursday, almost 8 years later, a Roadster climbed a curved ramp, dropped, rolled through the air and landed on its wheels. It used the same basic technology: cold-gas thrusters fed by high-pressure air stored in composite pressure vessels.

The 2019 exchange was not Musk’s first mention of thrusters. In June 2018, he said the Roadster would include roughly 10 of them and suggested they might allow the car to fly.

When another user proposed compressed-air cold-gas thrusters, Musk said that configuration made sense and described a pump to replenish the air.

Musk's account of the technology has proved more consistent than his production timetable. Tesla unveiled plans for the second-generation Roadster in 2017 and originally targeted production for 2020. After repeated delays, Musk said in the reveal that production will begin in 2028.

The Roadster is not Tesla’s only vehicle to miss an ambitious release target. When Musk unveiled the Cybertruck in 2019, he said Tesla expected production to begin in late 2021. The first customer deliveries took place two years later, in November 2023.

While Musk has missed plenty of deadlines, many of his more improbable technology plans have made it beyond the drawing board. In December 2020, he said SpaceX would try to catch a returning Super Heavy booster with its launch tower.

Nearly four years later, the tower’s mechanical "chopsticks" caught one for the first time.

Musk has a habit of promising the improbable well before it is ready, but eventually, the improbable part arrives.