In a first, China launched a rover on Saturday that will land on the far side of the moon, according to the official Xinhua news agency. This would provide a fillip to China’s ambitions of becoming a space superpower. The Chang’e-4 lunar probe mission — named after the moon goddess in Chinese mythology – was launched on a Long March 3B rocket from the southwestern Xichang launch centre in the pre-dawn hours. The launch marked the start of the journey to the unexplored side of the moon, which is mountainous and rugged. It is expected to land around the New Year to carry out experiments and explore the untrodden terrain. The near side of the moon is “tidally locked” and always faces the earth, and offers many flat areas to touch down on.
It was only in 1959 that the Soviet Union captured the first images of the heavily cratered surface, uncloaking some of the mystery of the moon’s “dark side”. No lander or rover has ever touched the surface there and if the Chang’e-4 manages to do the same, it will be global first. A major challenge for such a mission is communicating with the robotic lander: as the far side of the moon always points away from earth, there is no direct “line of sight” for signals.
As a solution, China in May blasted the Queqiao satellite into the moon’s orbit, positioning it so that it can relay data and commands between the lander and earth.
According to the Chinese state media, Chang’e-4 was being sent to the Aitken Basin in the lunar South Pole region known for its craggy and complex terrain. The probe was carrying six experiments from China and four from abroad. They include low-frequency radio astronomical studies aiming to take advantage of the lack of interference on the far side mineral tests, and experiments planting a potato and other seeds.
To add to the challenges, during the lunar night — which lasts 14 earth days — temperatures will drop as low as minus 173 degrees Celsius, while during the lunar day, also lasting 14 earth days, temperatures rocket as high as 127°C. Instruments must withstand those fluctuations and generate enough energy to sustain it during the long night.