China will launch its second space lab on Thursday, official media said Wednesday, as the Communist country works towards setting up its own space station, among several ambitious goals.

The Tiangong-2, or Heavenly Palace-2, will be sent into orbit from the Jiuquan Satellite Launch Centre in the Gobi desert, the official news agency Xinhua reported.

Engineers had begun injecting propellant into the Long March-2F rocket that would carry it aloft, it cited Wu Ping, deputy director of China's manned space engineering office, as saying.

Once it is in place the Shenzhou-11 mission will take two astronauts to the facility, where they will stay for 30 days, she added.

China is pouring billions into its space programme and working to catch up with the US and Europe.

It announced in April it aims to send a spacecraft "around 2020" to orbit Mars, land and deploy a rover to explore the surface.

Beijing sees the military-run programme as symbolising the country's progress and a marker of its rising global stature.

The nation's first lunar rover was launched in late 2013, and while it was beset by mechanical troubles it far outlived its expected lifespan, finally shutting down only last month.

But for the most part China has so far replicated activities that the US and Soviet Union pioneered decades ago.

It intends to build a Chinese space station, and eventually put one of its citizens on the surface of the moon.

China's first space lab, Tiangong-1, was launched in September 2011 and ended transmissions in March this year, when it had "comprehensively fulfilled its historical mission", Xinhua quoted Wu as saying.

It is expected to fall back to Earth in the second half of next year, she added.