BEIJING (AP) — A Chinese space capsule bringing back the first moon rocks in more than four decades has begun its return to Earth.

The Chang’e 5 lunar probe left the moon’s orbit on Sunday morning by activating four engines for about 22 minutes, the China National Space Administration said in a social media post.

The mission landed on the moon earlier this month and collected about 2 kilograms (4.4 pounds) of samples.

The return capsule is expected to land in northern China in the Inner Mongolia region after a three-day journey. The material would be the first brought back since the Soviet Union’s Luna 24 probe in 1976.