An uncrewed Chinese spacecraft returned to Earth Tuesday carrying the first soil and rock samples taken from the far side of the moon.

The Chang’e-6 probe landed Monday afternoon in northern China’s Inner Mongolia region, ending a historic mission that began in early May when it was launched from a spaceport on the island province of Hainan.

Zhang Kejian, the head of the China National Space Administration, declared the mission “a complete success” shortly after the probe’s landing. President Xi Jinping issued a message calling the Chang’e-6 mission “a landmark achievement” in China’s efforts to become a space and scientific power.

The Chang’e-6 probe landed on the moon’s far side on June 2 on the South Pole-Aitken Basin, a wide impact crater that is one of the largest in the solar system. The probe used a drill to collect materials below the surface and placed them in a container in separate part of the spacecraft that blasted off from lunar surface two days later.

The materials collected from the far side could provide clues about the origins of the moon and solar system because its craters have fewer ancient lava flows than the near side.

Chang’e-6 is the second Chinese probe to collect samples of lunar soil and rocks and bring them back to Earth, after Chang’e-5 retrieved samples from the near side of the moon in 2005.

The Chang’e lunar probes are part of Beijing’s ambitions to compete with traditional powers the United States and Russia in a new space race. China has established its own permanent crewed space station and plans to send a crewed mission to the moon by 2030.

Some information for this report came from The Associated Press, Reuters, Agence France-Presse.