On Saturday, private spaceflight company Sierra Nevada announced that its Dream Chaser spaceplane had successfully glided and landed on a runway after being released from a helicopter. The stunt, done at Edwards Air Force Base in Southern California, is known as a free-flight test and is meant to test out the vehicle’s landing capabilities. It’s an important milestone in the Dream Chaser’s development, as Sierra Nevada readies the plane for spaceflight.

Resembling a mini Space Shuttle, the Dream Chaser will soon be used to send cargo to and from the International Space Station as part of NASA’s Commercial Cargo Program. Right now, two companies — SpaceX and Orbital ATK — hold contracts with NASA to periodically resupply the station through 2018. But last year, NASA awarded a second round of contracts, in order to cover cargo shipments to the ISS from 2019 through 2024. Sierra Nevada was picked for that round, along with SpaceX and Orbital ATK again. The company expects to start cargo missions sometime in 2020.

SNC is proud to announce the Dream Chaser® spacecraft had a successful free-flight test today @EdwardsAFB, with support of @NASAArmstrong. The Dream Chaser had a beautiful flight and landing! pic.twitter.com/lAn0n7FPsg — Sierra Nevada Corp (@SierraNevCorp) November 12, 2017

The Dream Chaser is a fairly unique vehicle compared to the other two companies’ spacecraft. Both SpaceX and Orbital ATK developed wingless cargo capsules that launch to the station on top of the companies’ rockets. Orbital ATK’s capsule — known as Cygnus — is then designed to burn up in the Earth’s atmosphere once it leaves the station, while SpaceX’s Dragon cargo capsule can survive the descent to Earth, using parachutes to land in the ocean. The Dream Chaser, however, which is meant to launch on top of an Atlas V rocket, glides down to Earth like a plane after reentering the atmosphere, landing horizontally on a runway.

Originally, Sierra Nevada had hoped its Dream Chaser would carry astronauts, and not just cargo, to the ISS. Back in 2010, NASA awarded the company $20 million to develop the Dream Chaser as a crewed vehicle, and Sierra Nevada did a ton of tests over the next couples of years to prepare the spacecraft for carrying passengers. But in 2014, NASA didn’t pick the Dream Chaser to do crewed flights to the ISS, going with SpaceX and Boeing’s proposed vehicles instead. Since then, Sierra Nevada has been modifying the Dream Chaser to just carry cargo, though the company is leaving the option open to develop a crewed version of the vehicle in the future.

This weekend’s free-flight test was the second one that Sierra Nevada has done with Dream Chaser. The first one, back in 2013, didn’t go all that smoothly: the vehicle’s landing gears failed, causing the spaceplane to crash-land and then skid off the runway. This landing and flight, however, was deemed a success, according to Sierra Nevada. The test vehicle was dropped from an altitude of a little less than 12,500 feet and reached a maximum speed of 330 miles per hour during the 60-second flight. “Everything went very well for us,” Mike Sirangelo, corporate vice president of Sierra Nevada Corporation, said during a follow-up press conference this afternoon. “Overall our parameters in the test were met or exceeded in our minds.”

Sierra Nevada doesn’t expect to do any additional flights with this test vehicle if the data from this event is good, though the company says this particular Dream Chaser could fly again if needed. The data gathered from this test will then be used to refine the development of the company’s first vehicle that will go to orbit, which is currently under construction. That Dream Chaser will also go through extensive testing before its first flight to space, which will be the company’s first operational flight for NASA.

Though, it’s not just NASA that plans to use the spaceplane: the United Nations also has a deal with Sierra Nevada to fly payloads to orbit from other countries on the Dream Chaser, starting sometime in 2021. And Sierra Nevada hopes to find other customers for the vehicle in the future, too. So once this spaceplane is ready for spaceflight, it could have a lot of work to do.

Update November 13th, 4:45PM ET: This article was update to include new information from a Sierra Nevada press conference.