The Shenzhou X spacecraft, which will be launched between June and August, has completed testing and on Sunday left Beijing for the Jiuquan Satellite Launch Center in Gansu province.

On its mission, it will carry three astronauts and dock with the orbiting Tiangong-1 lab module.

Tiangong-1 was launched in September 2011 and docked with the unmanned Shenzhou VIII that year and with the manned Shenzhou IX in 2012.

Shenzhou X will carry out the first formal application of the manned space transportation system.

It is the technological successor to the Shenzhou IX and will help the space transportation system move from the testing phase to the application phase, according to Bao Weimin, a technological division chief with China Aerospace Science and Technology Corp, which manufactured the spacecraft.

"It will also help set up a transportation system for doing research on space labs and the construction of a space station," Bao was quoted as saying by China Central Television.

The new spacecraft will also carry out some new experiments on orbiting.

Bao said, "There might be more than one interface on a space station and a spacecraft may need to orbit to dock with different interfaces from different directions. So we need to further assess these orbiting functions."

Zhang Bainan, chief designer of the Shenzhou X, said its key task is to find and tackle problems that may occur during the construction of a space station through orbiting Tiangong-1.

China plans to build a space station around 2020.

The mission will, for the first time, see astronauts deliver a science lecture to young people from space.

The nation has launched four unmanned and five manned Shenzhou spacecraft and the unmanned Tiangong-1 space module since the manned space program started in 1992.