Chang’e-4 lander and Yutu-2 rover. Images of each other taken by the respective machinery.

China’s Chang’e-4 lander/rover is about to be cold-soaked, as darkness falls on the Von Kármán crater landing site.

On January 3, the probe softly touched down on the South Pole’s Aitken Basin on the farside of the Moon.

China’s Xinhua news agency reports that the farside Moon mission is equipped to measure the moody Moon swings of temperatures. The lunar day equals 14 days on Earth, and a lunar night is the same length.

Sleep mode

“Without our own data about lunar temperatures, we don’t know how cold a lunar night can actually be,” Zhang He, executive director of the Chang’e-4 probe project from the China Academy of Space Technology (CAST) told Xinhua.

Tan Mei, a Chang’e-4 consultant from CAST, said the lander will switch to a “sleep mode” during the lunar night due to the lack of solar power, and rely on a radioisotope heat source to maintain warmth. This power supply is the product of collaboration between Chinese and Russian scientists.

“We need to transform heat into power to run the thermometry to measure the temperatures of the lunar surface at night,” Tan said.

Moon Control room.
Credit: CCTV/Screengrab/Inside Outer Space

Data collectors

The lander is equipped with dozens of temperature data collectors, and the data they collect at night will be transmitted after the probe is wakened during the Moon’s daytime, said Li Fei, a designer of the lander from CAST.

As reported by Xinhua, Sun Zezhou, the chief designer of the Chang’e-4 probe from CAST, said the probe will get first-hand data by directly measuring the temperatures of the lunar soil, probe’s surface, and its key interior equipment during the lunar night.

Used for the first time in a Chinese spacecraft, the isotope thermoelectric generation technology on Chang’e-4 is a prototype for future deep-space explorations, Sun said.

Queqiao relay spacecraft is in a halo orbit around the second Lagrangian (L2) point of the Earth-Moon system, utilized to set up a communication link between the Earth and the Moon’s farside. Credit: CCTV/Screengrab/Inside Outer Space

In 2013, China launched Chang’e-3, the country’s first spacecraft to soft-land on the moon. The scientific instruments on its lander are still operating after more than 60 lunar nights in the past five years.

Relay link

In May of last year, China sent a relay satellite, named Queqiao, meaning Magpie Bridge, to the halo orbit around the second Lagrangian (L2) point of the Earth-Moon system to set up a communication link between the Earth and the Moon’s farside. It is the first communication satellite operating in that orbit.

According to Xinhua, Chinese space experts hope Queqiao will be able to assist other countries that intend to send probes to the farside of the Moon within the relay spacecraft’s life span.

China’s lunar exploration will continue with Chang’e–5, which is expected to bring samples of lunar soil back to Earth.

Courtesy of New China TV, posted on January 13, watch this video about the Chang’e-4 mission and outreach to other nations:

3 Responses to “China’s Chang’e-4 Moon Mission: Facing the Big Freeze”

  • Enrique says:

    Congratulation for this impressive achievement. I have a suggestion to make: why not send some specimens of the so-called “water bears” to the Moon. Could they survive there? Thanks. Best regards

  • Just read that the germinating cotton pkant has succumbed to the cold of a lunar night. I am wondering why the exoeriment did not include a heater in the biotome canister?

  • Frank Schmidt says:

    so what’s the story – did the rover survive the night

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