Virgin Orbit launched a rocket from a specially modified Boeing 747 on Wednesday, clearing the way for the company to launch a similar rocket into space later this year.

A spinoff of Virgin Galactic, Virgin Orbit plans to launch small satellites into low-Earth orbit from a plane instead of from the ground.

Wednesday’s test flight from Edwards Air Force Base was the culmination of nearly five years of work. The Virgin Orbit team had to heavily outfit its 747 — dubbed Cosmic Girl — to hold the LauncherOne rocket under its left wing.

https://twitter.com/Virgin_Orbit/status/1137134593444798465

“We started flying with just Cosmic Girl alone, then added the pylon, and finally the rocket underwing. Since last November, we’ve flown nearly a dozen times with a heavyweight rocket,” the company tweeted just before the successful rocket test.

The air launch essentially simulated much of what would actually happen if a rocket was sent into space. The Virgin Orbit team filled their LauncherOne rocket with water and antifreeze to make it as heavy as a real rocket, according to The Verge. Chief Test Pilot Kelly Latimer flew the jet to 35,000 feet and dropped the rocket to the Mojave Desert below. Without any major problems, the equipment seems primed for a test launch into space.

https://twitter.com/Virgin_Orbit/status/1148988591407656960

The rocket was loaded with sensors that track whether everything was performing as expected. Between that and videos, the Virgin Orbit team should have a pretty good idea of how an actual rocket would perform during a space launch.

“The rocket will be telling us where it is, any motions that it’s feeling, and how it’s flying those first few seconds, which are very important for an air launch rocket especially,” Virgin Orbit CEO Dan Hart told The Verge.

The successful test should also be a boon to Virgin Galactic, which also plans to use the air launch technique to send tourists to space in a “spaceplane.”

“Cosmic Girl is back to straight and level flight, and #LauncherOne looked fantastic in the air today,” Virgin Orbit tweeted shortly after the test drop.

https://twitter.com/Virgin_Orbit/status/1148999490109526016

Once the air launch system has been adequately tested, Virgin Orbit plans to start launching actual satellites into space on behalf of a number of clients.