Chang 'e 1 satellite was developed by China Academy of Space Technology and named after Chang 'e, an ancient mythical figure in China. It is mainly used to obtain three-dimensional images of the lunar surface, analyze the distribution characteristics of related material elements on the lunar surface, detect the thickness of lunar soil, and detect the space environment of the earth and the moon. In the initial sample development stage, two initial sample satellites, namely the electric satellite and the structural satellite, undertake satellite testing. Chang 'e-1 platform is developed on the basis of China's mature Dongfanghong-3 satellite platform, with a star diameter of 2,000 mm×1720 mm× 2,200 mm, fully inheriting the existing mature technologies and products of China Resources-2 satellite and China-Pakistan Earth Resources Satellite, and making adaptive transformation. The so-called adaptive transformation is an innovation in inheritance and a breakthrough in a number of key technologies.
On October 24th, 20071Beijing time 10, the probe was successfully launched from xichang satellite launch center.
general situation
Chang 'e-1 is a cube with two solar panels on each side, with a maximum span of 18.438+0m, a weight of 2350kg and a working life of one year. It will run in a circular polar orbit 200 kilometers from the surface of the moon.
The satellite platform consists of nine subsystems: structural subsystem, thermal control subsystem, guidance, navigation and control subsystem, propulsion subsystem, data management subsystem, measurement and control data transmission subsystem, directional antenna subsystem and payload. These subsystems perform their respective duties and work together to ensure the smooth completion of the lunar exploration mission. The payload on the satellite is used to complete the scientific exploration and test of the moon, and other subsystems provide support, control, instruction and management services for the normal work of the payload.
According to the four scientific objectives of China's lunar exploration satellite project, Chang 'e-1 carried eight kinds of 24 scientific detection instruments weighing 130 kg, namely microwave detector system, gamma spectrometer, X-ray spectrometer, laser altimeter, solar high-energy particle detector, solar wind ion detector, CCD stereo camera and interference imaging spectrometer.
According to aerospace experts, the test of electric satellites is mainly used for the comprehensive test of some equipment with electronic performance, and the test of structural satellites is mainly to assess the rationality of structural design and the rationality of temperature control design of the whole satellite. At present, the structural manufacturing of these two prototypes has been completed, and the whole satellite test will be started before the end of the year. On this basis, the prototype satellite of Chang 'e-1 will be developed. According to reports, the whole initial sample testing stage will last until June 2007, and then it will enter the development stage of satellite-like stars.
In order to ensure the completion of the lunar exploration project, researchers designed 4 1 item reliability for the Changsanjia rocket undertaking the satellite launch mission to improve its carrying reliability.
Chang 'e-1 is China's first artificial satellite orbiting the moon. Named after China's ancient mythical figure Chang 'e, it was launched in xichang satellite launch center at about 18: 05 (UTC+8: 00) on October 24, 2007, and the whole process of "flying to the moon" took about 8-9 days. It is estimated that the total weight of the satellite is about 2350kg and its service life is more than 1 year. The main detection objectives of the satellite are: to obtain three-dimensional images of the lunar surface; Analyze the content of useful elements on the surface of the moon and the distribution characteristics of material types; Detect the thickness of lunar soil and the space environment from the earth to the moon.
Technical difficulties
1, Orbit Design and Flight Program Control
2. Three-vector control problem of satellite attitude control.
3. Adaptive design of satellite environment
4, remote measurement and control and communication problems
Chang 'e-1 satellite was developed by China Academy of Space Technology. It is mainly used to obtain three-dimensional images of the lunar surface, analyze the distribution characteristics of related material elements on the lunar surface, detect the thickness of lunar soil and detect the space environment of the earth and the moon. Chang 'e-1 lunar exploration satellite consists of a satellite platform and a payload. The satellite platform was developed with the technology of Dongfanghong-3 satellite platform, and the researchers made adaptive modifications to eight subsystems, including structure, propulsion, power supply, measurement and control, and data transmission. Payload includes CCD stereo camera, imaging spectrometer, solar cosmic rays monitor, low-energy particle detector and other scientific detection instruments.
Chang 'e-1 lunar exploration satellite was launched by the Long March 3A carrier rocket in xichang satellite launch center in June 2007. After the satellite is launched, it takes 8 to 9 days to complete the phase modulation orbit, the earth-moon transfer orbit and the orbit around the moon, and carry out scientific exploration tasks. It will complete four scientific tasks, the primary purpose of which is to "portrait" the moon, that is, to obtain images and three-dimensional images of the moon surface through various means. In addition, it is necessary to analyze the distribution characteristics of useful elements and material types on the surface of the moon, and detect the thickness of lunar soil and the space environment of the earth and the moon.
According to experts, Chang 'e-1 satellite is two meters square. When the solar wing is deployed, it can reach18m at the longest, and its takeoff weight is 2350kg. It takes 10- 12 days for a satellite to fly near the moon. The design life of Chang 'e-1 is one year, and it will not return to Earth after completing its mission.
prepare
The lunar exploration program has been brewing for 10 years.
As early as 1994,
1996, research on technical scheme of lunar exploration satellite.
1998 to complete the research on key satellite technologies, and carry out further demonstration in the later stage.
test
The payload prototype system of Chang 'e-1, the first satellite of China's lunar exploration program, is undergoing the final joint test to ensure the normal work of scientific exploration equipment in space in the future.
The development and testing of the payload of Chang 'e-1 satellite is the responsibility of the Space Science and Applied Research Center of Chinese Academy of Sciences. In an interview with 16 on June 6, Wu Ji, chief commander of the payload and director of the space science and application research center, said: "In the final stage of the joint test of the payload prototype system, all developers should continue to maintain a rigorous and meticulous working attitude and complete the joint test of the prototype according to the quality requirements to ensure the smooth delivery of the payload equipment and the successful completion of the engineering task."
The satellite payload varies with different space missions. At present, it is mainly instruments for scientific exploration and equipment for scientific experiments. The payload of Chang 'e-1 satellite will include microwave detector subsystem, space environment detection subsystem and payload data management subsystem.
It is understood that the microwave detector subsystem will mainly estimate and evaluate the thickness of lunar soil, which is the first time in the world to detect the lunar surface by passive microwave remote sensing. The space environment detection subsystem consists of three devices, such as solar high-energy particle detector, which will detect the space environment parameters of the earth, the moon and the near moon.
Chang 'e-1 was launched in 2007, followed by a year of lunar exploration.
After long-term preparation and demonstration in 10, the lunar exploration project in China was formally established in 1 month in 2004, and it was called "Chang 'e Project". At present, the project mainly carries out lunar exploration, three-dimensional image analysis of the moon, global content and distribution survey of useful elements and material types of the moon, lunar soil thickness detection and space environment detection of the earth and the moon.
launch
Chang 'e-1 satellite will be put into geosynchronous elliptical orbit after launch, with the shortest distance of 200 kilometers from the ground and the longest distance of 5 1000 kilometers. The lunar exploration satellite will orbit this orbit for 1.6 hours, and then enter a larger elliptical orbit by accelerating, with the shortest distance from the ground of 500 kilometers and the longest distance of 1.28 million kilometers. Since then, the exploration satellite has been accelerating and began to "rush" to the moon. After about 1 14 hours of flight, when it is about to reach the moon, it will slow down by controlling the rocket's reverse booster. After being "captured" by the gravity of the moon, it became a satellite orbiting the moon, and finally flew around the moon in the polar lunar orbit at a height of 200 kilometers from the surface of the moon, and carried out work such as shooting three-dimensional images.
The total time for the satellite to fly to the moon is 1 14 hours, which is close to 384400 kilometers from the earth. In the past, the satellites launched by China were generally about 35,800 kilometers above the ground, which was almost 10 times.
Countdown to Chang 'e-1 launch
36 hours: Some systems carry out the final "physical examination".
12 hours: enter the pre-launch function check state.
8 hours: Enter emission process, and all systems make auxiliary preparations.
7 hours: Fill with liquid oxygen.
5.5 hours: filling liquid hydrogen.
2 hours: Enter the pre-launch system. The ground began to power up the system, and at the same time began to issue various passwords.
40 minutes: The revolving platform of Tower 3 begins to unfold.
15 minutes: the last batch of personnel are evacuated.
90 seconds: power on. Power supply supplies power to the system from the ground to the battery inside the system.
60 seconds: the orange cable pendulum rod extending from the back of the tower to the front tower is set out at this time, ready to ignite and launch the rocket.
40 seconds: Commander 0 1 begins to report the countdown.
30 seconds: pull. It used to be the exclusive command of the launch system. Although the related system is no longer used, this program has been used until today.
10 second: ignition countdown.
0 seconds: ignition.