NASA’s Artemis II mission successfully fired its engines and left Earth orbit, marking the first time humans have done so since the Apollo 17.

The crew—three Americans from the United States and one astronaut from Canada—are now on a trajectory toward a lunar fly-by, traveling nearly 250,000 miles from Earth.

The translunar injection burn occurred about 25 hours after liftoff and was reported to be flawless.

Astronauts described the experience as extraordinary, taking in “phenomenal” views as they departed Earth, the AP has reported.

The mission is a key test flight that will pave the way for future lunar exploration and long-term human presence on the Moon.