China's high-stakes mission to the moon's 'hidden' side

China will attempt to land a spacecraft on the northeast side of the moon's south pole, described by scientists as the "golden belt" for lunar exploration.

China's Chang'e-5 probe after its separation from the ascender, at the Beijing Aerospace Control Center (BACC) in Beijing Sunday, Dec. 6, 2020. Image AAP

China is poised to send a robotic spacecraft on a round trip to the moon's far side in the first of three missions that will pave the way for an inaugural Chinese crewed landing and a base on the lunar south pole.

This week, China is expected to launch its Chang'e-6 mission using a backup spacecraft from a 2020 trip, and collect soil and rocks from the side of the moon that permanently faces away from earth.

With no direct line of sight with the earth, Chang'e-6 must rely on a recently deployed relay satellite orbiting the moon during its 53-day mission, including a never-before-attempted ascent from the moon's "hidden" side on its return journey home.

The same relay satellite will support the uncrewed Chang'e-7 and 8 missions in 2026 and 2028, when China starts to explore the south pole for water and build a rudimentary outpost with Russia. China aims to put its astronauts on the moon by 2030.

The Chang'e missions are named after the mythical Chinese moon goddess.

Beijing's polar plans have worried NASA, whose administrator Bill Nelson has repeatedly warned that China would claim any water resources as its own.

Beijing says it remains committed to co-operation with all nations on building a "shared" future.

On Chang'e-6, China will carry payloads from France, Italy, Sweden and Pakistan, and on Chang'e-7, payloads from Russia, Switzerland and Thailand.

NASA is banned by US law from any collaboration, direct or indirect, with China.

Under the separate NASA-led Artemis programme, US astronauts will land near the south pole in 2026, the first humans on the moon since 1972.

Chang'e 6 will attempt to land on the northeast side of the vast South Pole-Aitkin Basin, the oldest known impact crater in the solar system.

The south pole has been described by scientists as the "golden belt" for lunar exploration.

Polar ice could sustain long-term research bases without relying on expensive resources transported from earth.

Chang'e-6's sample return could also shed more light on the early evolution of the moon and the inner solar system.