BEIJING, Oct. 30 -- Chinese research vessel and icebreaker Xuelong (Snow Dragon) set off on Thursday from Shanghai on the country's 31st Antarctic expedition, scheduled to return in April next year.

An important task for the mission is the building of a base station for the BeiDou navigation satellite system. The base will provide data and technical support for the navigation system and for Antarctic surveys and mapping, according to Liu Cigui, director of the State Oceanic Administration.

The mission will also select a site for an airstrip for fixed-wing aircraft on the ice sheet near the Zhongshan research base. The airfield will be a significant step forward for research boosting staff and materials transportation and emergency response.

Scientists will study local ecosystems, survey the areas and map them, observe any changes in ice and snow conditions and carry out a geomagnetic survey at the Great Wall, Zhongshan and Kunlun stations.

Research in hydrology, meteorology, marine geology, marine biology and other subjects will be carried out in the Southern Ocean.

The expedition team consist of 281 members from the Chinese mainland, Taiwan, Thailand and Turkey.

This is the 30th year of China's Antarctic missions.