Beijing, China - Jan 14, 2019 (CCTV - No access Chinese mainland)
1. Media briefing in progress
2. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 probe (starting with shot 1/partially overlaid with shots 3-4):
"Communication relay is a necessary condition for the soft landing on the far side of the Moon. But at the same time, the complicated terrain on the far side of the Moon poses a huge challenge to landing and cruise exploration. We mainly used two means to ensure the safe soft landing on the far side of the Moon. The first is to raise the precision for soft landing. Only by improving the accuracy of landing, can we find a relatively safer landing zone in the rugged area. Judging from the landing result, we may say that we have achieved the landing accuracy as designed. The second is to adopt the relay obstacle avoidance method. To realize soft landing on the complicated terrain, it is necessary to avoid obstacles in the process of landing. The adoption of the relay avoidance means effectively prevented the lander from meeting obstacles."
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3. Reporter asking questions
4. Various of reporters taking pictures
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5. Various of journalists at press briefing
6. SOUNDBITE (Chinese) Sun Zezhou, chief designer, Chang'e-4 probe (starting with shot 5):
"You might have seen the image of the terrain around the landing zone. It rises and falls sharply, full of big and small impact craters. So it is very difficult for the rover to do the detection. We dealt with this problem mainly from two aspects. First, to refine the planning. We carried precise ground restoration of the images perceived by the rover and mapped out more reasonable route for the rover, striving to find a relatively safer route. Second, to give full play to the capabilities of the rover so that it can independently avoid obstacles."
7. Journalists at media briefing
8. Media briefing in progress

China adopted two means to enable the soft landing of Chang'e-4 on the complicated terrain on the far side of the Moon, said the chief designer of the probe on Monday.

Sun Zezhou told a media briefing in Beijing how China achieved soft-landing on the far side of the Moon.

"Communication relay is a necessary condition for the soft landing on the far side of the Moon. But at the same time, the complicated terrain on the far side of the Moon poses a huge challenge to landing and cruise exploration. We mainly used two means to ensure the safe soft landing on the far side of the Moon. The first is to raise the precision for soft landing. Only by improving the accuracy of landing, can we find a relatively safer landing zone in the rugged area. Judging from the landing result, we may say that we have achieved the landing accuracy as designed. The second is to adopt the relay obstacle avoidance method. To realize soft landing on the complicated terrain, it is necessary to avoid obstacles in the process of landing. The adoption of the relay avoidance means effectively prevented the lander from meeting obstacles," said Sun.

The complicated terrain added to the difficulty of the rover Yutu-2 (Jade Rabbit-2)'s patrolling and image processing.

"You might have seen the image of the terrain around the landing zone. It rises and falls sharply, full of big and small impact craters. So it is very difficult for the rover to do the detection. We dealt with this problem mainly from two aspects. First, to refine the planning. We carried precise ground restoration of the images perceived by the rover and mapped out more reasonable route for the rover, striving to find a relatively safer route. Second, to give full play to the capabilities of the rover so that it can independently avoid obstacles," said Sun.