Astronauts on the Shenzhou X mission replaced the interior cladding of the Tiangong-1 space module on Friday, completing their first maintenance job in space.

Commander Nie Haisheng, astronaut Zhang Xiaoguang, and Wang Yaping, the second Chinese woman in space, removed the soft floor inside the 10-meter-long space module, and installed new cladding.

A news release from the manned space program did not detail the total area of the floor involved.

"The new cladding is conducive for astronauts to stabilize their body in the micro-gravity environment," an expert was quoted as saying in the release.

The change of cladding was also aimed at helping engineers improve the design of future space labs, the expert said.

The release did not detail how long the replacement took, but previous space missions by other countries have showed that it usually takes longer for astronauts to fix things in space than on Earth.

The mission's spokeswoman Wu Ping said previously that there will be more replacement work carried out on some seal rings inside the Tiangong-1 during the mission, meaning similar fixing work lies ahead for the astronauts.

On Friday, the three also moved supplies from Shenzhou X to Tiangong-1, and rechecked the condition of the space module.

Although Tiangong-1 has been uninhabited for the year since the previous mission crew lived in it for nearly 10 days last June, the astronauts confirmed the air quality, moisture and temperature levels inside the module remained normal.

The Shenzhou X spacecraft blasted off from Jiuquan Satellite Launch Center in Gansu province on Tuesday. The mission will last for 15 days.

The spacecraft conducted a successful docking with the orbiting Tiangong-1 at 1:18 pm on Thursday. The three astronauts moved into the module three hours later and all remain in good condition.

Wu said that the astronauts will have more rest than the previous crew.

During the Shenzhou IX mission, one astronaut of the three remained on duty all night to watch out for any unexpected incidents.

But during the current mission, staff on the ground will monitor the condition of the space vessels, and alert the astronaut on night shift to any emergencies, China Central Television reported.

In the coming days, the astronauts will carry out more space-science and technical experiments, and give their first lecture to students on the ground, said spokeswoman Wu.