In the Mojave Desert, California, a company called Stratolaunch has just unveiled the world’s biggest plane, which will one day be used to launch small satellites into space.

The huge vehicle boasts two cockpits and six Boeing 747 engines. It spans a whopping 117 meters (385 feet) and weighs about 230,000 kilograms (500,000 pounds). It is 73 meters (239 feet) long and 15 meters (50 feet) tall. That wingspan is needed to support small rockets, which the plane will carry to a high altitude and drop. These will then launch into space and put small satellites into orbit.

The 28 wheels of the plane felt the full weight of the plane for the first time these last few weeks, as the plane was rolled out of an equally huge hanger. The company said that the initial aircraft construction phase is now complete, and they would now begin ground testing. They are hoping to fly the thing for the first time in 2019.

“Over the coming weeks and months, we’ll be actively conducting ground and flightline testing at the Mojave Air and Space Port,” the company said in a statement. “This is a first-of-its-kind aircraft, so we’re going to be diligent throughout testing and continue to prioritize the safety of our pilots, crew and staff.”

One of the first rockets the plane will launch is the Pegasus XL, an air-launch vehicle developed by Orbital ATK. This has launched more than 40 times previously on an L-1011 plane, but last year they signed an agreement with Stratolaunch to use its vehicle.

And there’s a good reason for that. Stratolaunch will be able to carry three Pegasus rockets, not just one, something that’s not been done before. It can also carry a combined payload weight of up to 250,000 kilograms (550,000 pounds), which is pretty impressive.

The company was founded by Paul Allen, a co-founder of Microsoft. Allen made waves in 2004 when another of his companies, Scaled Composites, became the first to send a private space plane into space and back called SpaceShipOne. That company was later bought by Virgin Galactic, ultimately leading to their SpaceShipTwo vehicle that will one day take paying customers to space.

Stratolaunch will not be the only plane capable of launching rockets into space. Aside from the L-1011, Virgin Galactic’s White Knight Two has also flown several times. But it might just be one of the most impressive.

“We have a lot of exciting activity ahead as we enter the testing process, and we look forward to sharing our progress during the coming months,” the company said.