On October 24, 2007, Chang'e-1Xichang Satellite Launch CenterLaunch[1]；On March 1, 2009, Chang'e-1 completed its mission and hit the predetermined place on the moon surface[2]。
The success of Chang'e-1 satellite's first lunar exploration has set up the third milestone of China's aerospace, and has broken through a large number of core technologies and key technologies with independent intellectual property rights, making China one of the few countries in the world withDeep space explorationCapable countries[3]。
In 1994, China organized relevant experts to conduct a preliminary analysis and demonstration of the necessity and feasibility of lunar exploration, and believed that China had the ability to carry out lunar exploration, but due to various reasons, the lunar exploration plan could not be launched[4]。
In August 2000, a review team composed of nine academicians including Wang Daheng and experts from the General Armament Department, Aerospace Science and Technology Group, the Ministry of Science and Technology, the Chinese Academy of Sciences and universities was established to demonstrate and review the "scientific objectives and payloads of lunar resource exploration satellites" proposed by the Chinese Academy of Sciences[4]。
In 2001, an expert research group composed of relevant units of the Chinese Academy of Sciences was established, and research on key technologies such as payloads and ground application systems began;In October, China's lunar exploration program was approved[4]。
In March 2002, the project establishment report of "Feasibility of Lunar Resources Exploration Satellite Project" was submitted[4-5]。
R&D process
In January 2004, the first phase of China's lunar exploration project was officially launched, and all work entered the project implementation stage[4]；On February 25, the "Chang'e Project" of China's lunar exploration project was announced to be implemented;On April 30, Chang'e-1 passed the detailed design review of the prototype, and the satellite entered the prototype development stage[6]。
In November 2005, Chang'e-1 completed its prototype development;In December, Chang'e-1 passed the whole satellite prototype design review, and the satellite entered the prototype development stage[6]。
On January 19, 2007, Chang'e-1 passed the factory review of the whole satellite;In February, the launch window of Chang'e-1 satellite was adjusted to October 2007;In August, Chang'e-1 was again ready to enter the site[6]。
system composition
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The Chang'e-1 star is a cube, with a solar panel on both sides, the maximum span of 18.1 meters, the weight of 2350 kilograms, and the working life of one year[7]。
The Chang'e-1 satellite platform consists of nine subsystems, namely, structure subsystem, thermal control subsystem, guidance, navigation and control subsystem, propulsion subsystem, data management subsystem, TT&C data transmission subsystem, directional antenna subsystem and payload.These subsystems perform their duties and work together to ensure the successful completion of the lunar exploration mission.The on-board payload is used to complete the scientific exploration and test of the moon, and other subsystems provide support, control, command and management assurance services for the normal operation of the payload[8]。
At 18:3:30 on October 24, 2007, the Long March 3A rocket switched from ground power supply to its own power supply, and three batteries were installed in the rocket instrument cabin, the third stage tail compartment, and the second stage interphase section;18: 05, Chang'e-1 was launched;18: At 05:04, Chang'e-1 was launched[1]。
148 seconds after launch, the first and second stages of the rocket separate;In 243 seconds, the fairing separated and the rocket flew out of the dense atmosphere;The second and third stages of the rocket separated in 271 seconds;In the 609th second, the three-stage engine was shut down once, and the satellite rocket combination entered the gliding phase;In 1249 seconds, three-stage secondary ignition;In the 1373 second, the tertiary secondary engine shuts down;In 1473 seconds, the satellite and arrow separated and Chang'e-1 entered orbit[1]。
At 18:45 on October 24, 2007, Chang'e-1 established a cruise attitude;At 19:00, the Chang'e-1 solar array was successfully launched and began to absorb solar energy to power the satellite;At 19:10, Chang'e-1 entered orbit accurately[1]。
Chang'e-1 orbit change
On orbit operation
On October 25, 2007, Chang'e-1 carried out its first orbit change, and the perigee height of the satellite rose from about 200 km to about 600 km[11]。
On October 26, 2007, Chang'e-1 made its second orbit change and entered the 24-hour orbit[12]。
On October 29, 2007, Chang'e-1 made its third orbit change[13]。
On October 31, 2007, Chang'e-1 carried out the fourth orbit change, and entered the earth moon transfer orbit from the earth orbit[14]。
On November 5, 2007, Chang'e-1 entered lunar orbit[15]。
On November 7, 2007, Chang'e-1 established a three body orientation attitude.
On December 11, 2007, "Chang'e-1" has explored the back of the moon and obtained images[16]。
On March 1, 2009, Chang'e-1 successfully impacted the moon under control[2]。
Impact site
Chang'e-1 lunar impact site is located in the rich sea area of 52.36 degrees east longitude and 1.50 degrees south latitude of the moon[17]。
Chang'e-1 "collides with the moon"
technological innovation
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Technical breakthrough
Track design technology
In order to make Chang'e take pictures of the moon surface at any position on the lunar orbit, with the same resolution, and the orbit height required to be stable, Chang'e-1 has chosen the lunar polar orbit for its working orbit, with a height of 200 kilometers and an operation period of about 127 minutes.Chang'e-1 needs the least energy to operate in this orbit, and has the lowest risk during launch and orbit change, which has accumulated experience for China's lunar exploration project and subsequent deep space exploration orbit design[18]。
Antenna technology
The antenna aperture is proportional to the detection distance. Increasing the antenna aperture can increase the space TT&C distance and improve the deep space detection capability of the space TT&C network.The Chang'e-1 team has newly built two antennas with a diameter of 18 meters in Kashi Station and Qingdao Station, which has improved the remote measurement and control accuracy, extended the measurement and control distance of the ground station from the earth's short range to the moon's range, and ensured that Chang'e-1 can still establish a good wireless communication link for satellite ground data transmission and measurement and control signals in the space 4.0 × 105 kilometers away from the earth,It has laid a solid foundation for Chang'e-1 to successfully complete its operation and scientific exploration tasks[18]。
First use of ultraviolet lunar sensor
Chang'e-1 uses ultraviolet lunar sensors to observe the moon, which can meet the needs of various lunar phases, including the new moon, the first quarter moon, the full moon, the last quarter moon, and even when there is a total solar eclipse. Without the support of the ground station, it can directly obtain the elevation angle and rolling angle of the moon, and determine whether the flight orbit of the lunar probe is parallel to the moon surface[18]。
Three body orientation
Chang'e-1 adopts three body orientation: the solar cell wing is oriented to the sun, the exploration instrument is oriented to the moon, and the transceiver antenna is aimed at the earth.Chang'e-1 is the first to use the dual axis antenna autonomous pointing control technology, which enables the antenna to move freely up and down, left and right, and can achieve high-precision pointing and positioning requirements in hemispherical space, thus having the ability to track and point the earth, accurately transmitting scientific exploration and telemetry data back to the earth, and reducing the power consumption of communication antenna[18]。
thermal profile
When Chang'e-1 goes around the moon, it will be affected by the sun, moon, moon shadow, earth shadow and cold space background. The external thermal environment is very harsh and complex. The temperature of the moon surface changes violently, and the temperature difference varies between 120 and 180 degrees Celsius.Therefore, it is necessary to develop a temperature control system that can simultaneously adapt to the earth moon transfer and the lunar environment, so that Chang'e-1 can dissipate heat when it is hot and ensure the satellite temperature in cold environments[18]。
Space experiment
Experiment purpose
1. The Chang'e-1 satellite platform was tested under various extreme conditions to verify the response measures for various critical conditions, and then the satellite platform was designed and optimized to provide first-hand in orbit data.
2. This is an early test verification for China's subsequent lunar exploration mission.It provides a basis for the design of in orbit flight control program in the development of Chang'e-2 and Chang'e-3 satellites.
3. Through necessary long-life reliability assessment of some key equipment of the satellite, the possibility of performing more remote deep space exploration tasks is verified.
4. Obtain scientific detection data to the maximum extent through the startup test of the payload[19]。
Experiment content
S/N
Name of experiment
one
Long term operation test of ultraviolet lunar model
two
Verification test of solar wing high-temperature coping strategy
three
Experiment on obtaining cosmic background data of gamma spectrometer
four
Earth tracking experiment of directional antenna in sun oriented mode
five
On orbit test of GNC's autonomous orbit change capability
reference material:[19]
Honors won
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Winner
Awards won
Issued by
Chang'e-1 R&D Team
Special Award for Moving China in 2007
Moved China's Person of the Year Selection Committee
reference material:[20]
Overall evaluation
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During the one-year operation of Chang'e-1 satellite in orbit, 1.37TB of effective scientific exploration data were returned, and a batch of scientific research achievements were obtained, such as the image map of the whole moon, the distribution of some chemical elements on the moon surface, and the engineering and scientific goals were successfully achieved[21]。（Chinese government online review）
The in orbit test carried out by Chang'e-1 satellite has made full use of the satellite's life extension period and obtained a large number of valuable test data, providing basic data for the development of Chang'e-2 and Chang'e-3 satellites. It has important engineering, scientific and practical significance for the implementation of China's second phase lunar exploration project and other deep space exploration plans[19]。(People's Online Review)
The complete success of the first lunar exploration of Chang'e-1 satellite has set the third milestone of China's aerospace industry. It has broken through and mastered a large number of core technologies and key technologies with independent intellectual property rights, making China one of the few countries in the world withDeep space explorationCapable countries have achieved many "firsts" in China's space history and spacecraft: developed and successfully launched China's first moon orbiting exploration satellite for the first time;For the first time, it realized the flight around the moon and scientific exploration;The overall design idea and development process of deep space exploration mission have been formed for the first time, which fully reflects that China's comprehensive national strength has been significantly enhanced, and its independent innovation ability and scientific and technological level have been continuously improved[3]。（National Space AdministrationComment)
