Why did Shenzhou series spacecraft launch at Jiuquan Satellite Launch Center?

Xichang satellite launch center (XSLC), also known as Xichang Satellite City, was founded in 1970 and belongs to the General Armament Department of China People's Liberation Army. It is a space launch base that mainly undertakes the launch of geosynchronous orbit satellites, and undertakes the test launch and application launch tasks of communication, broadcasting and meteorological satellites. Xichang satellite launch center is the largest launch site in China, with the most advanced equipment and technology, undertaking the largest number of alien launch missions, and capable of launching multiple types of satellites. The launch center has test launch, command and control, tracking and measurement, communication, meteorology and technical service support systems. The two launching stations, technical test center, command and control center and other supporting facilities in the launch site area can undertake and complete all kinds of domestic and foreign satellite launching services. Among the three major satellite launch centers in China, the functions are relatively complete and the equipment is relatively perfect. It can launch both the Long March 3 series launch vehicle using cryogenic propellant and the bundled rocket with large carrying capacity. On June 24th, 2007 18: 05: 04 (UTC+8: 00), China's first man-made satellite around the moon, Chang 'e-1, was launched in xichang satellite launch center.

Jiuquan Satellite Launch Center, also known as "Dongfeng Space City", is one of the launch test bases of China's scientific satellites, technical test satellites and launch vehicles, the earliest and largest comprehensive missile and satellite launch center established in China, and the only manned space launch site in China at present. So all the Shenzhou manned spacecraft were launched here.

Zhang Jianqi, deputy commander-in-chief of China's manned spaceflight project and "Shenzhou VII" mission command, pointed out that the launch time of "Shenzhou VII" was mainly considered from a technical point of view to ensure the success of astronauts' extravehicular activities. For the "Shenzhou VII" astronauts to leave the cabin, the first thing we imagine is that the astronauts will leave the cabin on the sunny side to ensure the safety of the cabin, and the downloaded images will be clearer. We also hope that when the astronauts return, it will be as daytime as possible. It is difficult to fully meet these two requirements.

After a lot of calculations, the launch before the end of September can ensure that the sun will leave the cabin and it will not be too dark when it returns. According to the planned window from September 25th to 30th, if the launch time is selected at around 9: 00pm 10, the astronauts can be ensured to leave the cabin on the sunny side and return at around 5: 40pm, which is not too dark. This can ensure the astronauts to return safely, and it is also the embodiment of people-oriented. 10, especially after the middle of 10, the launch window is very narrow, which is not conducive to launch and recovery. In addition, around the autumnal equinox, the solar activity is more intense, which also has a negative impact on TT&C communication of spacecraft. In order to ensure the astronauts to walk in the continuous measurement and control band, and at the same time to facilitate image transmission under lighting conditions, Shenzhou VII spacecraft is required to launch at night and walk out of the cabin during the day.

Liu, chief meteorologist of Jiuquan Satellite Launch Center, said that according to the analysis of meteorological data for many years, the weather in Jiuquan Satellite Launch Center was mainly sunny at the end of September, especially in the evening, which was very suitable for spacecraft launch.