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Technical breakthroughs of Chang'e 2 satellite

09-25-2010 16:08 BJT

Compared to the Chang’e-1, the mission of the Chang’e-2 adopted many new technologies. The Chang’e-2 plays a key connecting role between the preceding and the following in the lunar exploration project, and has a very important significance to the project and even to the development of China’s aerospace cause. Compared to the Chang’e-1, the Chang’e-2 has more advanced technologies, more difficult missions, and more complicated systems. Technical innovations and breakthroughs will be realized in six aspects.

First, the technology of sending a satellite directly into the earth-moon transfer orbit by using a carrier rocket will be realized. The Chang’e-1 was firstly launched into the transitional orbit close to the earth, and then sent to the earth-moon transfer orbit after several adjustments, but the Chang’e-2 will be directly sent by the rocket to the earth-moon transfer orbit whose perigee is 200 kilometers and apogee is about 380,000 kilometers far from the earth. This way, the efficiency will be improved a lot. It took around 14 days for the Chang’e-1 to enter its working orbit, but it will take only seven days for the Chang’e-2 to do so. Compared to the Chang’e-1, the mission of the Chang’e-2 needs a more powerful carrier rocket and higher orbit-entering and control precision.

Second, the X Frequency Range Deep Space Measurement and Control Technology will be tested and the Deep Space Measurement and Control System will be put into preliminary trial. During the Chang’e-2 satellite’s mission period, the X Frequency Range Deep Space Measurement and Control System newly developed by China will be put into trial for the first time. Compared to the S Frequency Range Satellite Measurement and Control Network adopted on the Chang’e-1, the X frequency range radio communication equipment has higher signal frequencies and is more effective for long-distance communication.

Third, the technology of landing a satellite on the moon from an orbit of 100 kilometers will be tested. The Chang’e-1 was captured by the moon at a location 200 meters away, but the Chang’e-2 will brake and be captured by the moon at a location 100 meters away. The Chang’e-2 will have a higher speed, lower orbit and larger momentum, and meanwhile the uneven lunar gravity field will have a heavier influence on the satellite orbit. Therefore, the requirements on the Chang’e-2 satellite’s brake control precision will be much stricter.

Fourth, the 100 kilometers × 15 kilometers orbit changing and fast orbit measuring technology will be tested. The Chang’e-2 will test the 100 kilometers × 15 kilometers orbit changing and fast orbit measuring technology. The Chang’e-2 satellite’s ability of changing its round orbit with a radius of 100 kilometers into an elliptic orbit with a perigee of 15 kilometers and an apogee of 100 kilometers from the moon will be tested.

Fifth, the brand-new landing camera, which has a much stronger data transmission capacity, will be tested. The Chang’e-2 will be equipped with a landing camera, and its imaging capacity for the moon will be tested in order to make preparations for the soft-landing of the Chang’e-3. The data transmission speed will also be increased from 3 million bytes per second of the Chang’e-1’s to 6 million bytes per second on the Chang’e-2. An experiment to test the speed of 12 million bytes per second will also be carried out.

Sixth, a high definition imaging experiment for the pre-selected landing area of the Chang’e-3 will be carried out. The range resolution of the CCD camera carried by the Chang’e-1 was only 120 meters. But the camera on the Chang’e-2 will carry out imaging experiments with range resolutions superior to 10 meters and five meters in the perigees of the round orbit with a radius of 100 kilometers and the 100 kilometers × 15 kilometer elliptical orbit. The range resolution will be greatly improved.


There are mainly three risks when the Chang’e-2 performs its mission. The first is whether the rocket can accurately launch the satellite into the lunar trajectory, the second is whether the satellite can be successfully captured by the moon when it reaches the moon, and the third is whether the satellite can orbit 15 kilometers away from the moon.

Compared with the Chang’e-1, the Chang’e-2 must achieve a number of new breakthroughs and have innovations in many key technological areas. Therefore, the Chang’e-2 has more arduous tasks and risks. Thehe researchers are carrying out the task according to the requirements of "high standards, high quality and high efficiency".

Editor:Zheng Limin |Source:

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