Two Chinese astronauts aboard the Shenzhou VI spacecraft carried out experiments in the capsules yesterday, the second day of China's second manned space flight, while the vessel functioned normally.

The crew, Fei Junlong and Nie Haisheng, closed and reopened the internal cabin door and made express airproof tests on the door. They changed out of bulky space suits in turn in the return capsule, which is part of the planned anti-disturbance experiment.

They also moved smoothly between the orbital and re-entry capsules three times at the 20th circuit of the Earth and tested the condensation water extraction system.

Fei and Nie, who entered space on Wednesday morning, have exaggerated their movements in all the experiments in a bid to test the effects of their actions on the spacecraft.

Their movements created little disturbance to the spacecraft's stability and functions, and there was no need to make any adjustment to the flight as the spacecraft, which has circled the Earth 23 times so far, is orbiting normally.

The spacecraft is fully capable of sustaining all such disturbance, which allows the astronauts to move in a relatively free way, said Zhang Shuting, deputy designer of the spacecraft system. The pair's body functions, including the temperature and blood pressure, remained normal after over 34 hours' flight in space.

This far exceeded the 21.5 hours spent in space during China's first manned flight in 2003, when astronaut Yang Liwei became China's first man in space.

The two astronauts have had four meals and slept once in shifts, each for about seven hours, said doctor Li Yongzhi in the mission control center, confirming that the crew is healthy and in a good mood.

Although everything has proceeded smoothly so far, all scientific and technical staff need to be cautious, experts said.

The mission is the first time that Chinese astronauts participated in space experiments in a real sense since the launch of Shenzhou V. In that flight, Yang Liwei, China's first man in space, was strapped to his seat throughout his 14 orbits.

The Shenzhou VI is scheduled to have its first orbit maintenance operation in the early hours today, in order to restore the vessel to its original trajectory.

The spacecraft has slightly deviated from its designed orbit and moved a little closer to the Earth due to gravity.

Shenzhou VI is traveling at 7.82 kilometers per second in a circular orbit 343 kilometers above the Earth, after the orbit shift from an elliptical course in its fifth circuit.

Experts said the maintenance will be a normal technical operation and similar tasks are possible in the future.