Xichang Satellite Launch Center, Sichuan Province, southwest China - Recent (CCTV - No access Chinese mainland)
1. Moon
2. Satellite image of moon
3. Animations of probe landing on far side of moon
4. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 (ending with shot 5):
"Most of the far side of the moon are covered with high mountains, impact craters and lunar craters. It is difficult to find a large and flat area. this requires that we must be more accurate in fixing the landing site."
5. Various of probe, staff checking equipment
6. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 (starting with shot 5):
"There are some differences between Chang'e-3 and Chang'e-4. The Chang'e-3 landed on the moon following a parabolic path, but our Chang'e-4 will primary land vertically."
7. Staff checking equipment of probe
8. Animation of probe on moon
9. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 (starting with shot 8/ending with shot 10):
"Based on the supply of heat energy, we also try to use thermoelectric effect to generate power for the electronic equipment."
10. Animation of probes on moon
11. Animation of relay satellite supporting communication between moon, earth
12. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 (starting with shot 11/ending with shot 13):
"For future exploration of other planets, we need data relay. Actually, the relay satellites can provide a good solution, for example, we are working on data relay between the earth and the moon now, and will work on data relay from the Mars in the future. All these will contribute to the future advancement of technology and aerospace engineering."
13. Animation of relay satellite
14. Animations of probes on moon

Careful and solid preparations on the Chang'e-4 lunar probe launched in southwest China on Saturday have been done in order to ensure the probe's first-ever soft landing on the far side of the moon.

China launched its Chang'e-4 lunar probe in the early hours of Saturday at Xichang Satellite Launch Center in southwest China's Sichuan Province. It will land in the Von Karman crater in late December on the far side of the moon for the first time.

It's important to choose most appropriate landing point for lunar probe to explore the far side of the moon. Before China launched the Chang'e-3 probe, the scientists and researchers for probe launch had acquired abundant and accurate satellite images about the moon and the candidate landing site, Mare Imbrium (Sea of Rains), before making the final decision. But concerning the landing site selection for the Chang'e-4, no accurate images were available for reference, and the topographic conditions on the far side of the moon are more complicated than the Sea of Rains.

"Most of the far side of the moon are covered with high mountains, impact craters and lunar craters. It is difficult to find a large and flat area. this requires that we must be more accurate in fixing the landing site," said Sun Zezhou, chief designer of Chang'e-4.

The rugged terrain of the moon has not only increased the difficulty in locating the best landing point, but also will affect the probe's judgment of its distance to the surface of the moon and the relative velocity. As a result, a special design in the navigation control of the probe was adopted.

"There are some differences between Chang'e-3 and Chang'e-4. The Chang'e-3 landed on the moon following a parabolic path, but our Chang'e-4 will primary land vertically," said Sun.

With no access to the solar energy, the Chang'e-3 probe was totally power off in the nights on the moon, and all electronic equipment stopped work. But Chang'e-4 is equipped with a heating supply system, aimed to power the equipment.

"Based on the supply of heat energy, we also try to use thermoelectric effect to generate power for the electronic equipment," said Sun.

In addition, the Chang'e-4 will also use a relay satellite to achieve communication between the far side of the moon and the earth.

"For future exploration of other planets, we need data relay. Actually, the relay satellites can provide a good solution, for example, we are working on data relay between the earth and the moon now, and will work on data relay from the Mars in the future. All these will contribute to the future advancement of technology and aerospace engineering," said Sun.