Gearing up for Chang'e
China's deep-space network is ready for its first lunar spacecraft to launch.
February 14, 2007
This giant 50-meter dish is near the west bank of the Miyun Reservoir, in the northern outskirts of Beijing. It belongs to the National Astronomical Observatories of China in Beijing. The antenna's function is mainly data uploading and downloading during the Chang'e 1 lunar flight.
Photo by Renjiang Xie
|February 14, 2007|
China's first lunar spacecraft, Chang'e 1, is set to launch in April. Although China's existing S-wave-band space-monitoring network can meet the demand of a Shenzhou-series manned spacecraft, the diameter is not large enough for an interplanetary mission. In preparation for the mission, China built two VLBI antennae in 2006, one in Beijing and another in Yunnan, in southwest China.
The antennae measure 164 feet (50 meters) and 131 feet (40m), and both are undergoing tests now. According to Li Yan, director of the National Astronomical Observatories, Chinese Academy of Sciences, China now has four large radio telescopes within 1,900 miles (3,000 kilometers) of each other. The spacecraft will be launched from a CZ-3A rocket from Xichang Spaceport, in the Sichuan province of southwest China, and will enter a geostationary orbit before heading for the Moon.
China is just beginning to establish its deep-space network. Currently, two 60-foot (18m) antennae exist in Qingdao (in the Shandong province) and Kashi (in western Xinjiang); some smaller antennae exist in the Xi'an Satellite Monitoring & Control Center; and at Xichang Spaceport, there are four Yuanwang series space-monitoring ships. Yuanwang 5 and 6 are being built in the Jiangnan Shipyard of Shanghai and will be operational soon.
The Chinese space-monitoring network was started in the 1960s and was originally part of China's satellite surveying and control system, which is run by the People's Liberation Army (PLA). Apart from domestic monitoring sites, China has several monitoring stations in Pakistan, Namibia, and Kenya. This is the first time in Chinese space-mission history that China's VLBI network has coordinated its own interplanetary mission.
This 40-meter antenna on Phoenix Mountain of Kunming, Yunnan province, which weighs 400 tons, is a backup dish of Beijing's 50m antenna.
Photo by Renjiang Xie
According to Ouyang Ziyuan, lead scientist of the Chinese lunar-exploration project, during the flight of Chang'e 1, the European VLBI network will join China's deep-space monitoring and surveying. During ESA's Smart 1 lunar mission, China's 50m VLBI antenna in Beijing joined the monitoring work with two 25m VLBI dishes in Shanghai and Urumchi, proving that China's large antennae are at the same level as Europe and the United States'.
However, compared to the U.S. Deep Space Network, China's network is still in its infancy. China plans to build more large antennae in order to meet the demands of its ambitious, future deep-space missions.
Renjiang Xie is an amateur astronomer who lives in Dalian, China. He heads the largest Chinese astronomy web site, Astronomy Forum of Boötes.