China is poised to launch Chang'e-7, its most technologically complex lunar mission to date, in its search for frozen stores of water in permanently shadowed craters near the moon's south pole.
The uncrewed mission, named after a mythical Chinese goddess of the moon, will feature the deployment of a robotic lander, rover, and "hopping" probe to one of the coldest places in the solar system.
It will represent a major step towards Beijing's long-term goal of building a permanent human presence on the moon, with plans underway for a crewed lunar landing before 2030 and the setting up of a joint research station with Russia by 2035.
WHERE WILL CHANG'E-7 GO?
Next week, the Chang'e-7 spacecraft will lift off from the Wenchang Space Launch Site in the southern island province of Hainan atop a Long March 5 rocket with payloads that also include an array of scientific instruments such as water analysers, cameras and radars.
Once in orbit around the moon, the spacecraft will first examine potential landing sites at the south pole before a touchdown attempt.
One candidate location is near the rim of the Shackleton crater, a permanently shadowed depression. The jagged rim of the crater, however, is almost continually illuminated by sunlight.
China has not publicly disclosed a timeline for the Chang'e-7 mission, but space watchers estimate a landing attempt around November.
After touchdown, the rover and hopper will start surveying the surface.
The mission's duration remains unknown.
WHY THE SOUTH POLE?
Craters near the moon's south pole have not seen sunlight in billions of years. As such, scientists think they could act as deep freezers capable of preserving ancient water and volatile organic compounds.
Temperatures can drop to as low as minus 203 degrees Celsius (minus 334 Fahrenheit) in some of these shadowed terrain, according to NASA.
Finding accessible water is crucial for future lunar bases as it could provide drinking water, oxygen for astronauts, and even serve as raw rocket propellant, reducing the need for costly resupply missions from Earth.
Unlike most areas of the moon, where one lunar night is as long as 14 Earth days, the high peaks and crater rims near the south pole receive near-constant sunlight and would serve as an ideal location for a lunar outpost with a relatively stable thermal climate and continuous supply of solar power.
The United States, India and Russia have also set their targets on the moon's south pole. Only India landed nearby with its Chandrayaan-3 in 2023.
Over the coming years, NASA's VIPER rover, the European Space Agency's PROSPECT drilling package, and the Japan-India LUPEX rover are expected to arrive at the moon's south pole, as the race to find water sources intensifies.
A HOPPING ROBOT? IN THE DARKNESS?
One challenge for traditional wheeled rovers is the steepness of crater rims. To descend to the pitch-black floor of a crater, Chang'e-7 will deploy a novel hopping probe.
The hopper, equipped with a water molecule analyzer, will use its small thrusters to fly into shadowed craters. It will then land on six articulated legs, before hopping back to sunlit rims to recharge.
Technical details about the hopper's weight, engine performance, or flight range remain unknown.
China's state news agency Xinhua has reported that the vehicle is expected to conduct at least three hops during the mission.
WHO IS CHINA'S LUNAR COMPETITOR?
The data collected by Chang'e-7 and its successor Chang'e-8, planned for around 2029, will be crucial in China's plan for a crewed landing by 2030 as the two missions are meant to lay the groundwork for a permanently inhabited research station.
China's ambition to put humans on the moon and build an outpost near the south pole coincides with NASA's Artemis programme, which aims to return humans to the moon by 2028 and eventually establish a sustained human presence there.
