China's first space walk mission is now being scheduled for 2008, according to a top aerospace official.

The success of Shenzhou VI, which was launched last October with two astronauts orbiting the earth for five days, prompted speculation that China would launch Shenzhou VII to stage its first space walk next year.

But Zhang Qingwei, deputy chief commander of China's Manned Space Programme, told China Daily in an exclusive interview yesterday that safety and reliability, rather than time, was the priority for the launch.

He spoke to China Daily while attending the annual meeting of the National People's Congress, which opened yesterday in Beijing.

"We are carrying out a host of experiments centred on extra-vehicular activities of Shenzhou VII, which will carry three astronauts," said Zhang, also president of the China Aerospace Science and Technology Corp,

In preparation for the spaceflight, Chinese scientists are building a "water pool" and a weightless environment facility to train astronauts for extra-vehicular activities, Zhang said.

Usually, mission specialists receive extra-vehicular activity training in a large water pool, wearing a simulated space suit, according to space experts.

It will take some time for the country to complete various tests and trials, including those on space suits for a space walk, to ensure its third spaceflight is a success, Zhang said.

"To secure the reliability (of the technological changes to be made for Shenzhou spacecraft) as well as safety of astronauts, it is worthwhile for us to spend more time ... and readjust our initial plans," he said.

The spacecraft is no different in terms of size and shape when compared with Shenzhou VI, which was launched last October, Zhang said.

Zhang said that the Shenzhou VII will probably be launched sometime in 2008.

Huang Chunping, a chief consultant for China's manned launching vehicle system, echoed Zhang's remarks, saying that he expected the mission will be conducted in the second half of 2008.

He told China Daily it would give them sufficient time to improve space suits and the orbital module of the spacecraft. The improvements are expected to be completed next year.

Both Huang and Zhang stressed that China is well capable of making full preparations for the space walk.

They did not specify how many days the Shenzhou VII voyage will last.

All the three astronauts to fly Shenzhou VII will be selected from the same pool of 14 fighter-jet-turned pilots from which China's first three astronauts Yang Liwei, Fei Junlong and Nie Haisheng were chosen.

Although there will be no on-board engineers on Shenzhou VII, the country's subsequent space flights will increasingly involve such scientists, Zhang said.

"After we have tackled technologies regarding extra-vehicular activities and the docking of a manned craft with an orbital capsule, we will need many on-board scientists (for future space flights)," he said.

The official said earlier that with the development of China's manned space programme, the country will increase scientific research in orbit.

Scientists, including female experts, specializing in medicine, new materials, biology and other disciplines will all have the chance to work alongside astronauts, he said.

China carried out its maiden piloted space flight in October 2003, making the country the third in the world following the former Soviet Union and the United States to have put men into space.