China has launched the Chang’e 4 spacecraft to land on the largely unexplored far side of the moon from the the Xichang Satellite Launch Center in southwest China’s Sichuan Province this past Saturday.
The Chang’e 4 lunar probe was carried by the Long March 3-B rocket. The project is in collaboration with many countries, including the Netherlands, Germany, Sweden and Saudi Arabia.
The lander carries two cameras to observe the moon and the universe, including a German-built radiation experiment called LND and a spectrometer that will perform the low-frequency radio astronomy observations.
The rover has been loaded with a panoramic camera, a radar to probe beneath the lunar surface, an infrared imaging spectrometer to identify minerals and an experiment to examine the interaction of the solar wind with the lunar surface.
As the moon takes the same period to rotate on its own axis as it takes to complete one orbit of Earth, its orientation relative to the Earth is perpetually locked. Chang’e 4 is going to get a look at the hemisphere that we on Earth never get to see.
The communication signal will be completely blocked by the moon while the lunar probe is on the far hemisphere, making it more difficult to communicate with ground control and challenging for Chang’e 4 to accomplish its assignments. A relay satellite called ‘Queqiao’ in Chinese, launched in May this year, has to shoulder the communication task as a intermediary between the spacecraft and the launch center on the ground.
The lander and rover of Chang’e 4 are similar to the Chang’e 3, with a few upgrades and extra devices. The Chang’e 3 landed at the edge of the Mare Imbrium area of the moon, also known as Sea of Rains, in 2013 and deployed the Yutu rover.
There are dozens of peaks and large pits on the back of the moon, requiring a high-precision of landing. The landing site for Chang’e 4 is one of the oldest basins on the Moon, and may contain sections of exposed lunar mantle.
The Chinese Lunar Exploration Program initiated by China National Space Administration has been designed to be carried out in three phases: together with Chang’e 3, the latest mission is in the second phase of the program, targeting landing and roving on the Moon.
The first phase was simply reaching lunar orbit, a task completed by Chang’e 1 in 2007 and Chang’e 2 in 2010, while the third phase of Chinese Lunar Exploration Program is to collect samples from the near side of the moon and bring them back to Earth, a mission to be carried out by Chang’e 5 and Chang’e 6 in the near future.