Launch test of Shenzhou-9 spacecraft

China's manned space launch is mostly carried out in autumn and winter, and Shenzhou-9 spacecraft is launched in summer. The launch will face the test of weather conditions such as lightning, temperature and wind.

Among several meteorological conditions that may interfere with manned space launch, such as lightning, strong wind, precipitation and electric field intensity, lightning has the greatest influence. The meteorological data of 30 years from 198 1 to 20 1 1 show that there is basically no lightning in the launch site in autumn and winter, and the frequency of lightning in summer is about 2.6 times per month. For this seemingly insignificant figure, Li Xingdong explained that although this kind of minimum probability weather does not occur frequently, it may have disastrous consequences, and it is an internationally recognized field that is difficult to make accurate forecasts.

With the help of modern observation technology and numerical forecasting technology, nearly 30 forecasters are doing their best to make an accurate forecast of the weather conditions in the launch window of Shenzhou-9, providing reference for the launch. In addition, temperature is also an important factor in space launch. Rocket propellant may vaporize when the temperature is too high, solidify when the temperature is too low, and even cause some parts to fail.

Rocket system experts said that before the Shenjiu rocket was fueled, the warehouse where the propellant was stored would be cooled, effectively reducing the initial temperature of the fuel injected into the rocket. After filling, the temperature of the rocket is not easy to rise suddenly when the fuel quantity is huge and the rocket body is surrounded by the tower. Even in an emergency situation where the temperature rises sharply, displacement can be used to reduce the overall temperature of the propellant.

1June, 1997, on the eve of the launch of Fengyun-2 meteorological satellite by Long March III rocket, the temperature in xichang satellite launch center rose, and the staff took various measures to cool the rocket, even covered it with ice. Before the launch of Shenzhou IV on June 30, 2002, the temperature of Jiuquan Satellite Launch Center once dropped to minus 29 degrees Celsius, and quilts were used to keep the rocket warm. Some scientists predict that solar storms will peak in 20 12 and 20 13 years. Jiao Weixin said that the key to prevent the impact of solar storms on space activities is to make a good forecast.

Solar storms are usually accompanied by flare explosions, which can gather the ionosphere in a short time and affect the communication of spacecraft. At this time, the communication frequency can be changed, and in severe cases, important operations can be suspended to avoid launching and orbit change, so as not to cause great impact.

The Space Environment Research and Forecast Center of the Chinese Academy of Sciences forecasts the solar activity every day and provides it to the Beijing Flight Control Center in time, and the Beijing Flight Control Center makes timely adjustments to the Tiangong accordingly.

"This is called space weather forecast. The National Meteorological Administration, the Center for Space Science and Applied Research, and the national communications department are all doing it. There are corresponding plans according to different situations. Although it is not 100% effective, it is basically effective. "