Flowers on the Moon? China's Chang'e-4 to launch lunar spring

THE FAR SIDE

Tidal forces of the Earth have slowed the Moon's rotation to the point where the same side always faces the Earth, a phenomenon called tidal locking. The other face, most of which is never visible from the Earth, is the far side of the Moon.

With its special environment and complex geological history, the far side is a hot spot for scientific and space exploration. However, landing and roving there requires a relay satellite to transmit signals.

It has been reported that China plans to send a relay satellite for Chang'e-4 to the halo orbit of the Earth-Moon Lagrange Point L2 in late May or early June 2018, and then launch the Chang'e-4 lunar lander and rover to the Aitken Basin of the south pole region of the Moon about half a year later.

The Von Karman Crater, named after a Hungarian-American mathematician, aerospace engineer and physicist, in the Aitken Basin, was chosen as the landing site for Chang'e-4. The region is believed to have great scientific research potential.

The transmission channel is limited, and the landscape rugged, so the mission will be more complicated than Chang'e-3, China's first soft landing on the Moon in 2013, said Liu Tongjie, deputy director of the Lunar Exploration and Space Program Center of CNSA.

As the relay satellite will be sent to the Earth-Moon Lagrange Point L2 about 450,000 kilometers from the Earth, where a gravitational equilibrium can be maintained, it could stay in stable orbit and operate for a long time.

"We will make efforts to enable the relay satellite to work as long as possible to serve other probes, including those from other countries," said Ye Peijian,a leading Chinese aerospace expert and consultant to China's lunar exploration program.

The Lunar Exploration and Space Program Center of the CNSA has invited the public to write down their hopes for lunar and space exploration, and those hopes and the names of participants will be carried by the relay satellite into deep space. More than 100,000 people have taken part, according to the center.

INTERNATIONAL COOPERATION

As the far side of the Moon is shielded from electromagnetic interference from the Earth, it's an ideal place to study the space environment and solar bursts, and the probe can "listen" to the deeper reaches of the cosmos, said Liu Tongjie.

The Chang'e-4 probe will also carry scientific payloads developed by the Netherlands, Sweden, Germany and Saudi Arabia.

"The Chinese and Dutch low-frequency radio spectrometers might help us detect 21-cm hydrogen line radiation and study how the earliest stars were ignited and how our cosmos emerged from darkness after the Big Bang," said Chen Xuelei, an astronomer with the National Astronomical Observatories of the Chinese Academy of Sciences.

The rover will also carry an advanced small analyzer, developed in Sweden, to study the interaction between solar winds and the Moon surface.

And a neutron dosimeter, developed in Germany, will be installed on the lander to measure radiation at the landing site. Scientists say it is essential to investigate the radiation environment on the lunar surface in preparation for human missions.