China Launches Probe to the Dark Side of the Moon
In the early hours of Saturday, Dec. 8, the China National Space Administration (CNSA) launched its Chang’e-4 lunar probe on a pioneering mission to the far side of the Moon. A Long March-3B rocket was used to launch the probe, with its lander and rover, from Xichang Satellite Launch Center in Sichuan Province, southwestern China. The probe is expected to land in early January next year on the rugged terrain of the Moon’s far side — if successful, a first for lunar exploration — with the Von Kármán crater, located in the Aitken Basin near the southern pole of the Moon, being the area of interest for this mission.
Due to the phenomenon of tidal locking, the speed of the Moon’s rotation is synchronized with the daily rotation of the Earth. As such, one face of the Moon — the “near side” — always faces Earth and makes a direct line of sight to the “far side” of the Moon impossible. Combined with the rugged terrain of the area, landing a probe on the far side of the Moon is an extremely challenging mission.
In response to the anticipated challenges, CNSA launched the Queqiao satellite earlier this year in May. About a month after its launch, the satellite was able to successfully enter a stable orbit between the Earth and the Moon to await the arrival of Chang’e- 4 in order to establish communication links with the probe — otherwise impossible due to the tidally locked nature of the Moon to Earth — and relay its observations back to CNSA.
Apart from studying the crater to develop an understanding of the Moon’s mantle layer, the probe will also gather observations on the radio environment of the area by collecting radio observations at low frequencies, an otherwise impossible task on Earth due to its atmosphere. Inputs from its findings will be used to lay the groundwork for possible future construction of radio astronomy telescopes on the far side of the Moon.
Additionally, the probe’s lander also carries potato and Arabidopsis plant seeds to perform a “lunar mini biosphere” experiment developed by 28 Chinese universities. The experiment is designed to test the photosynthesis and respiration of plants in the low-gravity lunar environment.
Named after the Chinese Moon goddess, Chang’e-4 is the fourth mission of China’s lunar exploration program that started in 2004. Chang’e-3, its predecessor, was the launched in 2013, ultimately becoming the longest working man-made probe on the Moon.
While some observers have noted the relative dearth in coverage of the successes of the CNSA, especially with regards to China’s burgeoning space ambitions, others pointed to the relative silence of the CNSA on its missions, especially in comparison to the open publicity of NASA and ESA (European Space Agency) on their own missions. Parallels can be drawn between Chinese officials’ public interaction on Chang’e-4 and the Soviet government’s publicity strategy of its Space program during the Cold War — namely, silence until success allows for “the Chinese, like the Soviets, [can] boast about successes and downplay any failures.”
Aiming for further international cooperation in space exploration, Chang’e-4 also carries four scientific payloads developed by the Netherlands, Germany, Sweden, and Saudi Arabia. Apart from China, lunar missions of the Indian space agency and NASA are also expected to launch in 2019.