NASA’s rehearsal for Artemis II marks one of the final steps before four astronauts get launched into deep space for the first time since the Apollo program ended.

NASA says it is delaying its mission to send four astronauts on a journey around the moon after troubleshooting a liquid hydrogen leak during a critical test of the Artemis II rocket.

The Artemis 2 launch is aiming to send four other astronauts around the moon and back to Earth.