Xichang satellite launch center's lunar exploration project

On June 22, 2007, 10, Chang 'e-1 satellite was ready and ready to go. At about 18 on the 24th, Chang 'e-1 satellite was successfully launched here.

On June 24, 2007, Chang 'e-1, the first satellite of China's lunar exploration project, set off for the moon 380,000 kilometers away. The starting point of this mysterious space trip is xichang satellite launch center, which is located in the hinterland of Daliangshan Mountain in Sichuan.

In March 2004, the Commission of Science, Technology and Industry for National Defense and the National Space Administration announced that Chang 'e-1, the first satellite of China's lunar exploration program, would be launched in xichang satellite launch center in 2007 to carry out a mission around the moon. Why choose Xichang to launch Chang 'e-1 satellite?

It turns out that the "Chang 'e-1" of the lunar exploration project is the farthest satellite reached by China's space launch satellite. Not only does the satellite fly around the moon, but also higher requirements are put forward for the thrust and attitude control of the rocket. It is necessary to send a large thrust rocket into a geosynchronous elliptical orbit with a perigee of 200 km and an apogee of 5 1000 km. After experts' strict feasibility analysis of the Long March series rockets, the Long March 3A carrier rocket with strong carrying capacity and the highest launch success rate was finally selected to undertake the launch mission.

Among the four major satellite launch sites in China, xichang satellite launch center is the only launch site that can launch both geosynchronous orbit satellites and various types of satellites with various types of launch vehicles such as Long March 3A, so it is incumbent upon us to launch the first lunar exploration satellite.

Satellite launch is a complex system engineering, which needs the close cooperation and cooperation of all systems. It usually takes about 40 days from the arrival of rockets and satellites at the launch site to the launch. After a series of complicated processes, the star arrow was tested until it was launched. The lunar exploration project is the third milestone in China's space history. In order to ensure the success of the first launch, the preparation time for the launch of Chang 'e-1 satellite is relatively long.

After the rockets and satellites arrive at the launch site, they should be assembled and tested in their respective test halls. The test hall is equipped with high-power air conditioning to ensure the required temperature and humidity. Satellites have strict requirements for cleanliness, and people who come into contact with them should be wrapped all over and put on masks, just like the laboratories of the institute.

Ensuring the matching between on-board equipment and ground equipment and solving the problems in the test are the first level of the satellite at the launch site. After passing the test, the satellite will be refueled to meet the power demand of the satellite's orbit, attitude control and normal operation.

The rocket test hall is much larger than the satellite's, and it can test three rockets at the same time. However, based on their experience of more than 30 years, xichang satellite launch center reorganized the workflow and put most of the test items on the launch tower. In addition to the subsystem matching test, there are four large-scale general inspections to ensure that the rocket is trouble-free. There are two towers, No.2 and No.3, in the launch area. The existing No.3 launcher is a new type of tower rebuilt and built by the center in 2006 to adapt to the development trend of world space science and technology and meet the development needs of national space industry. Mainly used to launch the "Long March 3A" rocket. Launcher No.3 is 85.5 meters high, and the 12 working platform on the tower can rotate 180 degrees. The crane at the top of the tower is used to complete the erection, docking and hoisting of rockets and satellites. At the bottom of the tower, there is a launch pad for supporting rockets and a diversion groove that can withstand the erosion of high temperature and high speed airflow. Tower 3 is one of the most advanced rocket towers in the world.

In the eyes of ordinary people, weather forecast means high temperature and low temperature, windy and rainy, but here it is related to the success or failure of satellite launch. After the rocket and satellite pass the test in the launch area, depending on the weather and according to the orbit window of the satellite, it is decided whether to refuel or stand by and launch.

The so-called launch window is the time range during which the spacecraft is allowed to launch. The launch window of spacecraft is determined according to the space mission and external constraints. The external conditions affecting the launch window mainly include the orbital conditions of celestial bodies, the orbital requirements of spacecraft and the working conditions of spacecraft, as well as the launch direction, ground tracking control and meteorological conditions. As far as space missions are concerned, there are three launch windows. One is the annual window, which refers to the number of consecutive months in a specified year, and is suitable for interstellar exploration missions. The second is the monthly table window. It is expressed by the number of consecutive days in a month, which is suitable for planetary and lunar exploration missions; The third is the calendar window. It is expressed in the form of a certain time of a day to another time, which is suitable for all kinds of spacecraft.

The launch of Chang 'e-1 satellite, considering the shortest relative distance between the moon and the earth, has a better chance of rendezvous with the moon in orbit. It is only suitable for launching once a month, and each launch window is 35 minutes. If we miss the chance, the next launch will take a month. The boiling point of water is 100℃, while the boiling points of the other two liquids flowing in these pipes are -253℃ and-183℃ respectively. They are the most important propellants of rockets, called liquid hydrogen and liquid oxygen. At present, there are more than 100 kinds of liquid propellants that have been studied and put into test, which are divided into oxidant and combustion agent. Liquid oxygen, nitrogen tetroxide and nitric acid are commonly used oxidants, which mainly play a role in supporting combustion. Liquid hydrogen, kerosene and unsymmetrical dimethylhydrazine are combustion agents. Among these commonly used propellants, liquid hydrogen and liquid oxygen have the highest energy and the largest specific impulse.

Xichang satellite launch center is the only launch site in China that uses liquid hydrogen and liquid oxygen as cryogenic propellants. The third stage of the Long March 3A rocket is equipped with liquid hydrogen and liquid oxygen, and the propellants used in the first and second stages of the rocket are dinitrogen tetroxide and unsymmetrical dimethylhydrazine.

When refueling, the conventional propellants of the first and second stage rockets should be added first, and then the liquid hydrogen and liquid oxygen cryogenic propellants should be added to the third stage rockets seven hours before launch.

The lunar exploration project is another major milestone in the development of China's space industry and one of the "three major projects" carried out by xichang satellite launch center in recent years. Since its launch more than three years ago, the center has carried out hundreds of technical transformation projects of launch sites closely around the overall project goal of "realizing the first successful launch of the lunar exploration project" and the specific requirements of "carefully organizing, ensuring in place, testing and standardizing, and ensuring safety", realizing the remote test and launch control of rockets and satellites, continuously improving the comprehensive launch test capability, and providing a strong guarantee for the "first successful launch" of lunar exploration satellites.

From the beautiful legend of "the Goddess Chang'e flying to the moon" to the heroic practice of "thousands of families flying", from rushing out of the global village and landing on the moon to exploring Mars and flying to the Milky Way, mankind has never stopped exploring and pursuing mysterious space for thousands of years. 20 10 on September 29th, a spokesman for China's lunar exploration project announced that Chang 'e-2 satellite and rocket had completed the test and inspection in the launch site, and the test results were normal, which fully met the technical conditions for launching. It will ignite in xichang satellite launch center at 10, 1, 18: 59: 57 and take off at 19: 00 on time. If it can't be launched in the first window time due to weather and other reasons, we also choose to launch it on1October 2nd and 3rd, 65438.

20 10, 10, 1, 18: 59, 57 seconds and 345 milliseconds, Chang 'e II was successfully ignited, and the launch time was 19: 00. 29 minutes and 53 seconds after the flight, the star and arrow separated and the satellite entered orbit. 19: 56, the solar panel was successfully launched. At present, it has flown into the designated orbit.

The rocket wreckage launched by Chang 'e II crashed into the surrounding villages of Ji 'an City, Jiangxi Province at 10/month/day 1 9.

The main task of "Chang 'e II" is to obtain clearer and more detailed image data of the lunar surface and the surface data of the lunar polar region, so the resolution of the CCD camera carried by the satellite will be higher and other detection equipment will be improved. Some key technology experiments have been carried out to realize the soft landing of Chang 'e-2 moon, and the high-precision imaging of Chang 'e-2 landing area has been carried out to further detect the distribution of elements on the moon surface, the thickness of lunar soil and the space environment of the earth and the moon.

Sun Huixian, deputy chief designer of the lunar exploration project, revealed: "Actually, Chang 'e II is the backup star of Chang 'e I", and two satellites were prepared when launching Chang 'e I to ensure the success of the flight around the moon. "If Chang 'e-1 can't achieve its original goal, it may launch this spare star. The Chang' e-1 mission has been successfully completed, and this satellite has become the leading star of the second phase of China's lunar exploration project. " Chang 'e III is the lunar probe of Chang 'e II project of China National Space Administration, including lander and lunar rover. It is expected to be launched from xichang satellite launch center by Long March 3B in early February of 20 13. It will carry China's first lunar rover and realize China's first soft landing on the moon. On August 28th, 20 13, the State Bureau of Science, Technology and Industry for National Defense of China announced that the 11th meeting of the leading group for major projects of lunar exploration and the mobilization meeting for the launch of the Chang 'e-3 mission were held on the same day, and the Chang 'e-3 mission was reviewed and approved to be transferred from the development and construction stage to the launch implementation stage. Chang 'e-3 probe will be launched in xichang satellite launch center at the end of this year. On September/KOOC-0//KOOC-0/day, 2065438, Chang 'e III was transported by plane and arrived at Xichang launch site on June/KOOC-0/2/KOOC-0/0.

Chang 'e III was launched by Long March 3B on February 2, 20 13 1: 30.

Chang 'e-3 will be the first extraterrestrial soft landing probe and patrol vehicle (lunar rover) launched by China, and the first soft landing probe to return to the moon after Chang 'e-24, realizing the first soft landing on the lunar surface in China. Chang 'e-3 satellite is the lunar probe of the second phase of Chang 'e project of China National Space Administration. It carried out the first lunar soft landing and automatic patrol survey, obtained and analyzed the internal material composition of the moon, and extended the "surface detection" of the first phase of the project to internal detection. , the key task of the second phase of the lunar exploration project, plays a connecting role. The Chang 'e-3 lander carries a near-ultraviolet moon-based telescope and an extreme ultraviolet camera, and the rover carries a lunar radar. These are all pioneering works in the history of world lunar exploration. Chang 'e III will not only use some data verified by Chang 'e II, but also add ranging and speed measuring radar and laser rangefinder. Chang 'e IV is the backup star of Chang 'e III, but it will complete different exploration tasks.