Three Chinese astronauts Thursday entered a space module after carrying out a successful docking maneuver, state media said, two days after the launch of the country's longest manned space mission.

The astronauts entered the Tiangong-1 space module at 0817 GMT, almost three hours after their spacecraft Shenzhou-10 had linked up with the space laboratory in an "automated docking", Xinhua said, citing the Beijing Aerospace Control Center.

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The three -- who include China's second woman in space -- are spending 15 days in orbit as the country's ambitious space program reaches another milestone.

The docking procedure was the fifth to take place between Shenzhou-type spacecraft and the space module, Xinhua said.

Two automated operations were carried out by the unmanned Shenzhou-8 in 2011 and both an automated and manual docking by the manned Shenzhou-9 in 2012.

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Last year's manual docking, China's first, tested a technique that is needed to be able to construct a space station, which China aims to do by 2020.

Beijing sees the multi-billion-dollar space program as a symbol of its growing global stature and technical expertise, and of the ruling Communist Party's success in turning around the fortunes of the once poverty-stricken nation.

The screen at the Beijing Aerospace Control Center showing a simulated picture of an automated docking between the Shenzhou-10 manned spacecraft and the orbiting Tiangong-1 space module.Corbis