The leading candidate to be on China's first manned space mission, and in the process become a household name, was identified as Yang Liwei by a pro-Beijing newspaper.

The Hong Kong-based Wen Wei Po said Yang, who was born in 1965 and hails from Saizhong county in northeastern Liaoning province, topped a list of three astronauts who have been whittled down from an initial batch of 14 following physical and psychological examinations.

Second in the pecking order is Zhai Zhigang and third is Nie Haisheng, according to the newspaper.

However, it remains unclear how many astronauts will be inside Shenzhou V when it blasts off from the remote Gobi desert in north China's Inner Mongolia region sometime between Wednesday and Friday.

The Chinese government has been coy on the precise date but the chief designer of the craft's launch system said the launch window was very narrow.

"It is very difficult to satisfy all requirements simultaneously," Zhou Jianping was quoted as saying by the Xinhua news agency.

"The room is very small for choosing the 'window'."

The launch site, under clear blue skies, was sealed off Tuesday with a 10-man military blockade turning back vehicles without security clearance on the only road 35 kilometres (21 miles) south of the Jiuquan Launch Centre.

All systems though appear to be go.

The China News Service said a mock launch of the spacecraft was completed Monday and that the rocket was fuelled and in stand-by mode.

The simulated drill, which also involved tracking stations, started at 5:00 am (2100 GMT) and ran for three-and-a-half hours. The agency said there were no hitches.

If China succeeds in sending a man into orbit it will join an exclusive club whose only other members are the United States and Russia.

James Oberg, who worked at NASA mission control for 22 years, said he would be amazed if China only sent one astronaut in the three-man craft, as has been suggested.

"There is no good reason to restrict it to only one person," he said.

"If you see pictures of the cockpit, it is designed for at least two people. On the unmanned space flights they had two dummies on board."

The craft is expected to orbit the Earth 14 times, suggesting the flight will last 21 hours. State media have said it could land near Siziwang, some 100 kilometres (62 miles) north of the Inner Mongolian capital Hohhot.

President Hu Jintao is expected to fly to the launch centre late Tuesday and meet the astronauts, immediately after a key communist party meeting ends in Beijing.

He may be one of the few to witness the event as it happens after authorities decided against a live broadcast of the lift-off, state television sources and newspapers said.

"It won't be broadcast live. The launching unit doesn't want it to be broadcast live," said an official in the manager's office of the state-run China Central Television Station's Channel 9, an English channel.

"It's the same for all the CCTV channels," said the official, who declined to be identified. "It's been decided. This decision won't change."

Fear of public disappointment and criticism if the mission fails could be the reason behind the decision, analysts say.

With millions potentially watching, failure could mean a publicity disaster for the Chinese Communist Party, which hopes the flight will not only promote patriotism and national cohesion but legitimacy for its rule.

The government mouthpiece People's Daily also reported the decision.

"China's CCTV has announced its original plan of a live broadcast has been dropped," its website said Tuesday.

SPACE.WIRE