China enters the new moon race with Chang’e-1 launch

by Chris Bergin

At the beginning of a 35 minute launch window that opened at 10:05 UTC, a CZ-3A Chang Zheng-3A (CZ3A-15) was launched from the Xichang Satellite Launch Centre, located in Southwest China’s Sichuan Province, carrying the first Chinese lunar probe, Chang’e-1 (ChangEr-1).

This was the 104th successful orbital Chinese launch, the 45th successful orbital launch from Xichang, the ninth orbital Chinese launch in 2007 and the sixth launch from Xichang in the current year. Free launch video available (read more).



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“ESA’s expertise in tracking Chang’e-1 sets the stage for future cooperation with China. The Agency’s tracking station network, ESTRACK, is a resource that benefits not only the Agency but also all space science through such international cooperation,” said Erik Soerensen, Head of the System Requirements and Validation Section at ESA’s European Space Operations Centre, in a post launch reaction release.

Mission background:

After leaving Earth orbit on October 31, Chang’e-1 will initiate a five day journey until arrive into lunar orbit on November 5. The first image of the surface is expected at the end of November.< ?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

For centuries, Chinese mythology told the story of a beautiful woman that lived on the Moon for over 4000 years. The beautiful Chang’e was banished to the Moon because she stole the secrete of immortality from her husband. Within days the beautiful Chang’e will have another companion orbiting her house in the form of a Chinese lunar probe that marks the first phase of the China Lunar Exploration Plan (CLEP).

The CLEP is the third milestone for the < ?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />China’s Space Industry and was born in 1998, as part of a 211 step development plan for the Chinese space program. This plan originated from the work done since 1991, when Chinese experts proposed a lunar exploration program and conducted some advanced research on the theme.


The 211 step development plan had two objectives: the first being space applications and the second was deep space exploration.


The first objective of the plan developed heavy-lift launch vehicles, that will soon place heavy cargos Earth orbit. Other developments included the creation of satellite platforms, satellite applications and the development of Earth observation systems. The second objective is now hours of being launch into space: the lunar exploration program.


In November 2000, China issued its White Paper on Space Activities, clearly stating that the lunar exploration was to become the main objective of China’s deep space exploration.


According to Luan Enjie, Chief Commander of the Chang’e Program, China was careful in selecting its strategic approach to this program. This approach is a realistic one, with a guiding principle that has its focus on a gradual exploration aspect, with the aim to accumulate experience and knowledge.


With this, China has three objectives: to orbit the Moon, to land on the Moon and to return a sample of the Moon. These objectives will be achieved by, firstly, to launch Chang’e-1 to orbit the Moon, secondly, to launch a spacecraft that will deploy a lunar lander to explore the lunar surface, and thirdly, to implement a sample return mission on the basis of the previous spacecraft.


The first phase was initiated in January 2004, with the approval of the Phase I of the lunar exploration program. In Feb. 2004, the leading group for China’s Lunar Orbiting Exploration Project was established, and held its first meeting – where the general requirements. The development plan of Lunar Orbiting Exploration Project were determined and the lunar exploration program was named the Chang’e Program.


The design concept and development phase was completed in November 2004, and after this some technical problems were resolved, that permitted the construction of a prototype by December 2005. Flight model production started in 2006.


Chang’e-1 will not only be another lunar probe, with the mission having two generic objectives: technological and scientific. The engineering objectives of Change’-1 are the development and launch of China’s first lunar exploration satellite; the preliminarily mastering of the basic technologies for lunar orbiting exploration; to initiate lunar scientific exploration for the first time; and to initially establish lunar exploration engineering system and to accumulate experiences for follow-on projects of lunar exploration.


The scientific objectives of Chang’e-1 are to obtain three-dimensional images of the lunar surface, precisely ascertain the basic structures and physiognomy of the lunar surface, and to initially map out the lunar geology and structural elements to provide information for the follow-on soft landing.


Objectives also include the ability to detect and analyze the content and distribution of useful elements and types of materials on the lunar surface; to detect the characteristics of lunar soil and calculate the depth of lunar soil on the surface; to explore the space environment between the earth and the moon, and to record initial solar wind data and study the effect of solar activities on earth-moon space environment.


The Chinese probe is equipped with six payloads, with a total of 25 devices in eight instruments. These include and optical imaging system (CCD stereo camera and interferometer spectrometer imager), laser altimeter, Gamma and X-Ray spectrometers, Microwave detector, a space environment monitoring system (with a high-energy solar particle detector and a low-energy ion detector), and a system for the payload data management.


To achieve all its objectives, the Chang’e-1 will have to be manoeuvred to a specific orbital path around the Moon. The probe will achieve a low lunar polar orbit within altitudes of 100 km to 200 km.


This orbit allows the probe to meet the requirement of acquiring data with high resolutions. Chang’e-1 is also designed to be able to carry out a 90 degree rotation, by adopting two orthogonal flight attitudes, meeting the conditions required for illumination.


The probe his equipped with a gyroscope, accelerometer, sun sensor, moon UV sensor, star sensor, momentum wheel control and unloading, panel driving mechanism and thruster control.


The onboard guidance, navigation and control system has self diagnosis and certain fault treatment functions that can resolve some problems without the intervention of Earth controllers. The onboard computer adopts redundant design to ensure its reliable operation, and the Chang’e-1 satellite data management system has been modified adaptively based on the experiences of the previous satellites.

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