JIUQUAN - China is working on the development of a new generation of carrier rockets featuring a larger thrust to cater to the demand of building a space station, a chief rocket engineer said Thursday.

"The building of a space station requires carrier rockets with greater thrust as each capsule of the station will weigh about 20 tonnes," said Jing Muchun, chief engineer for the carrier rocket system of China's manned space program.

"We have been preparing for the launch of the space station slated for 2020," Jing told Xinhua.

The Tiangong-1, China's ?first space lab module, was launched into space by the Long March II-F T1 carrier rocket on Thursday evening, paving the way for a future space station.

Jing's deputy, Song Zhengyu, said the new generation of carrier rockets, represented by the digital and poison- and pollution-free Long March-V and Long March-VII, are expected to make their first lift-offs around 2014.

Song said the technologies applied to the new generation of carrier rockets will mature by 2021 and the existing Long March-II, -III and -IV series will be replaced sequentially.

China started developing modern carrier rockets in 1956, and the Long March rocket series has become the mainstream carriers for launching China's satellites.

The Long March rockets currently fall into four categories, namely Long March-I, -II, -III and -IV.