Stratolaunch, the gigantic aircraft backed by tech billionaire Paul Allen, rolled out of its hangar for the first time Wednesday, marking an important milestone for the project in its quest to reach the edge of the atmosphere.

The aircraft is indeed huge. It’s wingspan is 385 feet, or nearly double that of a Boeing ba 787 Dreamliner. Its length is 238 feet, 12 feet longer than the Dreamliner, with a tail that is 50-feet tall, or nearly the height of a five-story building. Here is a picture of the rollout.

The goal is for Stratolaunch to carry satellites close to space and then launch them before returning to Earth.

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To get to this point, technicians had to take down the scaffolding that supported the craft’s construction and make sure the Stratolaunch’s 28 wheels could support its 500,000-lb. weight. It was designed to handle a maximum takeoff weight, including cargo, of 1.3 million lbs., according to Stratolaunch CEO Jean Floyd.

The next steps? Ground and flight testing will take place at the Mojave Air and Space Port over the coming months, Floyd wrote.

Related: Gigantic Aircraft Backed by Tech Billionaire Paul Allen will Fly this year

Allen who made billions of dollars after starting Microsoft msft with Bill Gates in 1975, founded Stratolaunch in 2010 with a goal of making low-orbit launches more mainstream.

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Allen is not the only tech executive with aerospace ambitions. Elon Musk, CEO of Tesla tsla founded SpaceX to carry cargo to the International Space Station and eventually to transport passengers into space. And Amazon amzn founder Jeff Bezos is behind Blue Origin, a company that plans to use less expensive, reusable rockets to transport cargo.