BEIJING, Sept. 17 -- Zhai Zhigang, a reserve for the Shenzhou V and VI missions, is poised to become China's first spacewalker, reports have said.

Three 42-year-old astronauts - Zhai Zhigang, Liu Boming and Jing Haipeng - have been selected to carry out the country's third manned space mission, which will last from Sept 25-28, according to China.com.cn.

The most likely takeoff time for Shenzhou VII is 9:10 pm on Sept 25, the website said.

Shenzhou freshman Chen Quan leads the backup crew, which also includes Fei Junlong and Nie Haisheng. Fei and Nie were both onboard Shenzhou VI three years ago.

Upon the spaceship's entry into orbit a scheduled 582 seconds after liftoff, Jing will remain in the descent module while Zhai and Liu will move to the vacuum orbital module. Zhai is expected to conduct a 40-minute spacewalk between Sept 26 and Sept 27, with Liu as his substitute.

As part of the session, Zhai will retrieve an undisclosed amount of "solid lubrication material" placed beside the gate of the orbital module. Before he does that, Liu will help him put on a special spacesuit that weighs in at about 120 kg and is worth 100 million yuan ($14.6 million).

Zhai, a native of Heilongjiang province, will hold a private space-to-Earth conversation with his family during the mission, Astronaut Center of China (ACC) director Chen Shanguang said earlier during a briefing at the Jiuquan Satellite Launch Center in Gansu province.

The ranking of all six members of the crew has remained unchanged after successive physical and psychological tests by an expert panel that monitored, logged and reviewed their status around the clock, Chen said.

"That means the men we've selected are the most qualified for the task," he said.

Despite worries of airsickness, the preferred schedule for Zhai's spacewalk has been pushed forward to the end of his second day in space, Chen said.

The international routine is to spacewalk during an astronauts' third or fourth day in space.

All six members of the Shenzhou VII mission belong to China's first generation of 14 astronaut candidates, selected in 1998.

"All of them are at least 40 years old now after this mission, we will arrange for some of the astronauts' retirement or work transfers," Chen said.

The Shenzhou VIII and IX next year may well be farewell missions for China's first generation astronauts, sources with the ACC said.

Recent media reports have said plans for selecting a second group of Shenzhou astronauts - up to 14 people - are well under way.

Chen said everything is well prepared and that he will strive with all he has to draft new astronauts "once the announcement is officially made".

While there are no specific plans to find a female astronaut, Chen said the ACC is engaged in relevant "technical preparations".

Scientists have promised a record-high safety index of 0.997, which means that for every 1,000 missions, 997 astronauts will return safely.