China's first lunar probing satellite undergoes general assembly test
China has made smooth progress with its round-moon probing project, the "Chang'e 1" satellite, and its sample products have been turned out and passed appraisals before entering into the phase of system-level general assembly, integration and testing. The Satellite is expected to be launched at the Xichang Satellite Launch Center for a moon-encircling mission with four preset scientific goals, namely, drawing a three-dimensional moon map, analyzing the contents and types of chemical elements on the lunar surface and the types of moon materials, surveying the lunar soil and exploring the moon space environments.
Sun Laiyan, vice chairman of the Commission of Science, Technology and Industry for National Defense and director of China National Space Administration, made the above remarks at the 8th ILEWG Conference On Exploration and Utilization of the Moon on July 25th.
It is learned that China has made great progress in all five major systems: the project satellite, the launch vehicle, the observation and control, the ground application and the launch field through two and half a year's painstaking effort after the lunar probe project was initiated in 2004.
Chang'e 1" satellite has taken the platform of the "Dongfanghong No. 3 telecommunication satellite (or "DFH-3") as the foundation and is composed of seven kinds of science detecting instruments. The satellite changes the axle for several times by its own power after it separates from the rocket with three-axle stable attitude control. And it finally enters the 200-km-high polar lunar circular orbit after passing the phase modulation track and earth-moon transfer orbit.
The mature "Long March 3" A carrier rocket will be the launch vehicle. All-grade products have undergone test evaluations. And the comprehensive tests on electrical structures of the rocket will be conducted to determine the matching performance of the electrical system.
The observation and control system bases itself on China's existing observation and control facilities and fully utilizes the existing S frequency space instrumentation and command network, supplemented with long baseline interferometer astronomical measurement system. And the completion of the entire observation and control system is ascribed by optimizing designs, transformations and network organization.
The all-round tests of the entire system conducted in June this year have verified the capacity of observation and control network on tracking satellite, measuring the stationary orbit and carrying out observation and control in outer space.
With its task primarily to manage satellite in-orbit service function, data processing, scientific research and popularization, the ground application system has completed the preparations of the soils for four simulated moons and, through researches on simulated lunar soil, has acquired lunar soil's dielectric properties in the observation wave band and links between the temperature on the lunar surface and lunar soil's thickness under the specific conditions and it calculates inversely the thickness of lunar soil on the lunar surface and chemical properties of materials on lunar surface.
The simulated lunar soil has successfully been applied to payload science calibration experiments in "Chang'e 1" and the construction of simulated test field on the lunar surface.
It is reported that China's lunar project will take "three steps", that is, carrying out lunar surface inspection and prospecting, lunar surface soft landing and patrol, sample collection and a return-to-earth trip.
By People's Daily Online
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