China will launch new generation rockets with larger carrying capacities during the 12th Five-year Plan period (2011-2015), said Yuan Jie, deputy general manager of the China Aerospace Science and Technology Corp. (CASC) on Wednesday.

"The rockets in service cannot meet the demand from future manned space station, we need rockets with even larger carrying capacities," said Yuan.

He introduced the most representative new family members of rockets with larger carrying capacities: the large-sized Long March 5 and the medium-sized Long March 7.

The Long March 5 carrier rocket is the rocket with the largest carrying capacity under development in China and it will be mainly used for the launching of manned space station, said Yuan, adding it has a capacity of carrying 20-tonne payload to the near earth orbit.

The Long March 7 carrier rocket, with a carrying capacity of 13 tonnes for the near earth orbit, will launch the cargo spacecraft for the future manned space station, he said.

The new generation rockets employ numerous new technologies, in particular, they adopt new engines with non-toxic and no-polluting liquified propellent which are safer and more environment friendly, said Yuan.

The two types of rockets will be launched at a new launch site in south China's Hainan Province, and on the whole, development of the new-type rockets are well under way, according to Yuan.

"The maiden flight will be carried out during the 12th Five-year Plan period," he said.