JIUQUAN - The Shenzhou-9 manned spacecraft will face tests of thunder, high temperatures and other adverse weather conditions this summer ahead its launch, experts said Monday.

The spacecraft will be launched sometime in mid-June to perform the first manned space docking mission with the orbiting Tiangong-1 space lab module.

Li Dongxing, head of the meteorology office at the Jiuquan Satellite Launch Center, said thunder will be the greatest hazard for the craft, as well as heavy winds, precipitation and electric fields.

Meteorological statistics from the last 30 years show that thunder occurs near the center at an average frequency of 2.6 times per month during the summer, with almost no thunder in autumn and winter.

"Although extreme weather does not happen frequently, it can lead to disastrous results if it does happen," Li said.

With the help of advanced surveillance and data analysis technology, nearly 30 weather forecasters are doing their best to make precise forecasts for the craft's launch window, Li said.

High temperatures will also pose a danger to the craft, as the ship's propellant can vaporize in excessively high temperatures, as well as solidify if the temperature is too cool.

However, experts working on the ship's propulsion system said the propellant will be stored in cool rooms before the ship is fueled, adding that the propellant's temperature is not likely to fluctuate after it is pumped into the rocket.

Various methods have been employed to cool rockets or keep them warm in the past. Before the launch of the Fengyun-2 satellite in June 1997, experts applied cold compresses to the satellite's Long March-3 carrier rocket to cool it down after it experienced a surge in temperature at southwest China's Xichang Satellite Launch Center.

Before the launch of the Shenzhou-4 spacecraft on December 30, 2002, cotton quilts were used to keep the rocket warm, as temperatures fell to negative 29 degrees Celsius that evening.