What is the function of Chang 'e-2 lunar exploration satellite?

Chang 'e II plays a connecting role in the lunar exploration project!

Chang 'e II was developed on the basis of Chang 'e I satellite backup star. Its main task is to verify and detect the preliminary scheme for the second phase of the lunar exploration project, and it is the pathfinder for the second phase.

Compared with Chang 'e-1, Chang 'e-2 is newer in technology, more difficult, more complex in system and more risky. The "Chang 'e II" mission is like a springboard from Phase I to Phase II. It not only inherits many mature technologies of Chang 'e-1 satellite, but also adds many new technologies according to different mission objectives, which plays a connecting role in the lunar exploration project and is of great significance to the development of the whole deep space exploration cause.

Chang 'e-2 satellite, as the pilot star of the second phase of the project, is mainly used to verify some key technologies of the second phase of the lunar exploration project and deepen the scientific exploration target of the moon.

During the mission, Chang' e-2 satellite will carry out six technical verifications: first, it will cooperate with the launch vehicle to verify the direct launch technology of the earth-moon transfer orbit; The second is to verify the lunar orbit capture technology of near-lunar braking at a distance of 100 km from the lunar surface; The third is to verify 100 km× 15 km orbital maneuver and flight technology; Fourth, the high-resolution imaging test is carried out in the alternate area of the second phase project; Fifth, it is equipped with a lightweight miniaturized X-band deep space transponder to test X-band measurement and control technology with the newly-built X-band ground measurement and control station in China; Sixth, the low-density parity-check code (LDPC) coding technology of telemetry channel, high-speed data transmission technology between the moon and the earth and landing camera technology are tested. These six technical verifications will provide useful reference for us to further understand the lunar surface environment, grasp the development law of deep space exploration technology and effectively reduce the risk of the second phase of lunar exploration project.

On the basis of Chang 'e-1 satellite, Chang 'e-2 satellite has improved the payload performance and scientific detection accuracy of the moon. The key point is to achieve four scientific goals, that is, to obtain a more accurate three-dimensional image of the lunar surface, and the resolution is improved from 120 m of Chang 'e-1 satellite to 10 m or more. At the same time, it will also detect the moon's material composition, lunar soil characteristics and the space environment of the earth and the near moon. The scientific exploration of the moon by Chang 'e-2 satellite will play an important role in the follow-up lunar exploration in China, which can effectively promote the development of deep space exploration.

Chang 'e-2 satellite consists of 10 subsystem. According to the new mission requirements, the overall system and thermal control subsystem were redesigned. On the basis of fully inheriting the state of Chang 'e-1 satellite, eight subsystems were partially modified, while the technical test and payload subsystems concentrated all newly developed software and hardware products and were completely designed.

Create a "straight ladder." If Chang 'e II is compared to an acrobat who needs to complete a series of difficult movements in a harsh environment, then whether she can successfully enter the earth-moon transfer orbit is the first difficulty before her. According to the motion law of the base moon and the base sun, the window time for a satellite to enter the earth-moon transfer orbit is very short. If the satellite does not accurately enter the entrance of the earth-moon transfer orbit when the satellite and the arrow are separated, it is necessary to adjust the satellite orbit, which will cause the fuel on the satellite to be consumed in advance. If the deviation is too large, it will affect the implementation of subsequent tasks. Therefore, the satellite system and the rocket system cooperate with each other and go hand in hand. After repeated accounting, the launch orbit of the rocket is finally designed, creating a fast and convenient "direct ladder" for the Goddess Chang'e flying to the moon.

Ensure accurate "braking". After the ignition launch, "Chang 'e II" took the "through elevator" to the Moon Palace. If she runs too hard to brake in time, she can't be a moon satellite. Insufficient braking force will cause the satellite to fly out of the gravitational range of the moon and cannot be captured by the moon; If the "braking" force is too large, the satellite will hit the moon, and the consequences will be unimaginable. In order to make the satellite smoothly enter the working orbit of 100 km× 100 km and the orbit around the moon of 100 km× 15 km, the designer made an extremely accurate analysis and solution, established relevant mathematical models, and repeatedly confirmed the interface relationship between related systems. After repeated discussions and calculations, they finally found an effective method to control the accuracy, and the problem of accurate "braking" was solved.

Add a brand-new technical test subsystem. The biggest difference between Chang 'e II and Chang 'e I is the addition of a new subsystem-technical test subsystem. This subsystem is mainly used to verify the satellite-ground X-band measurement and control system, test the landing camera and other related technologies, and make preliminary verification and technical reserve for the second phase of the project. According to the satellite development node, this subsystem must complete the scheme design, the development of the initial sample and the normal sample products in the shortest time, so as not to affect the progress of the whole task. The task is urgent, and the research team of technical testing subsystem begins to wrestle with time. In the reference room, internet, design room and stand-alone factory, designers have been running around. After numerous calculations, arguments, overthrows, recalculations and re-arguments, the technical problems were finally solved one by one.

X-band measurement and control system was first applied in China. Chang 'e-2 satellite has many new technologies, a considerable part of which is the first experiment in the sky, and X-band measurement and control system is one of them. At present, the satellite-ground X-band TT&C system has not been applied to China satellite. Compared with the S-band TT&C system mainly used in China, it has the advantages of high transmission rate, small signal attenuation and more data. But at the same time, it also faces a series of technical problems such as design, devices and technology. Designers are not intimidated by difficulties, but face challenges directly. After studying all night, they finally came up with a solution in the shortest time.

Configure "heating and cooling air conditioning". Due to the change of orbit, Chang 'e-2 satellite will face a temperature difference of about 300℃ during its operation. How to resist the high temperature radiation from the sun and the cold below freezing point? The satellite radiation protection coating designed by the thermal control system design team of "Chang 'e II" shows its magic power. This golden coat, which is composed of 13 film as thin as cicada's wings, has a special structure, which can conduct the heat in the satellite and effectively form a thermal balance environment in the satellite. Chang 'e II put it on, just like being in an air-conditioned room with four seasons like spring.

Design a "combination of static and dynamic" miniature camera. In order to take a clear image of the earth from space after the launch of the satellite, and to obtain a quick and clear image of the lunar surface, Chang 'e-2 satellite is equipped with four miniature cameras integrating advanced technologies such as light, machinery, electricity and heat. According to the demand of Chang 'e-2 satellite, the designer took the initiative to tackle key problems and developed a short flat and fast camera by using CMOS image sensor.

After more than two years of research, the Chang 'e-2 satellite has made a breakthrough. In the Goddess Chang'e flying to the moon's Fantasy Circle Symphony, the strongest sound is played.