China's Chang'e 6 robotic probe completed the most important part of its lunar adventure on Tuesday morning when its ascender, carrying samples collected over two days in a sealed container, lifted off from the moon's far side.

The ascender — one of the four major components of the unmanned spacecraft — started its ascent engine at 7:38 am and flew for about six minutes before reaching lunar orbit, according to the China National Space Administration.

The return of the ascender to lunar orbit marks the successful completion of the first sampling and liftoff operations on the moon's far side by any country, the space administration said.

The Chang'e 6 probe, which represents the world's first attempt to bring samples from the lunar far side back to Earth, was launched by a Long March 5 heavy-lift carrier rocket on May 3 from the Wenchang Space Launch Center in Hainan province. It entered lunar orbit on May 8.

The 8.35-metric-ton spacecraft consists of an orbiter, a lander, an ascender and a reentry capsule.

After a host of sophisticated maneuvers, the lander touched down on the moon's far side on Sunday morning. It soon started using a scoop to collect surface regolith, the loose material covering solid rock, and a drill to dig up subsurface material.

At the same time, several mission payloads, including a panoramic camera, a lunar mineralogical spectrometer and a lunar soil composition analytical instrument, were activated for operation on the moon.