As China prepares for its upcoming manned space docking mission, experts at home and abroad are sketching new profiles of Chinese astronauts shaping the country's ambitions.

"In terms of their roles, astronauts are turning into 'drivers' rather than 'passengers'," according to He Yu, chief commander of the Shenzhou 9 spacecraft which on Saturday will be launched into orbit to dock with space lab module Tiangong 1.

Chinese astronauts Jing Haipeng (R), Liu Yang (C) and Liu Wang (L) will board Shenzhou-9 spacecraft on Saturday to fulfill China's first manned space docking mission. [Xinhua]

Its crew of Jing Haipeng, Liu Wang and Liu Yang was introduced to the public via a televised press conference on Friday.

It will be the second journey into space for 46-year-old Jing and the first space adventure for 43-year-old Liu Wang and the country's first female astronaut, Liu Yang, who is 33.

"Should any emergency occur, the human brain is more reliable than the computer," he said.

During the manned space flight, one of the three-member crew will manipulate the craft to couple with the space lab module with the assistance of the two others.

Also, the country's first manned rendezvous and docking mission between a spaceship and a space lab module will test the function of its spaceships as a transport carrier between the space and Earth, said Zhou Jianping, designer-in-chief of China's manned space program.

"It will be a new technology providing new means for the space docking to guarantee the success of future missions," Zhou said.

The upcoming mission marks progress in China's three-step process of building a space station around 2020.

In an email interview with Xinhua, Joan Johnson-Freese, an expert on China's space program at the U.S. Naval War College on Rhode Island, said it would be "a step forward" for China if the docking proves successful.

"China has already demonstrated docking technology robotics, so doing it manually this time is just another incremental step forward, with a robotic back-up for safety," she said.

But it won't be an easy job for the astronauts, according to Chinese and foreign space experts.

Precise control is needed to ensure a safe contact between two objects running at speeds between 7.9 kilometers per second (kmps) and 11.2 kmps, and the risks of the operation can not be verified firsthand via simulations on Earth, pointed out He Yu.

"There is only one chance for the success of the manual space rendezvous and docking," he said, adding, "Once collision happens and damage is caused to the machines, it means there will not be a second chance for the space module."

During the manual docking process, the main risks involve challenges to the optical sensors used for the docking of the craft, explained Erik Seedhouse, a Canadian space expert.

Force imbalances will result in other challenges in carrying out mechanical motions during separation control, he warned.

But as observed by Pat Norris, Chairman of the Royal Aeronautical Society Space Group, China has taken a prudent course of verifying new space technology in robotic flights before applying it to human space missions.

To succeed in the manned docking mission, Chinese astronauts have been trained more than 1,000 times for every single move before they are commissioned for the program, compared with 900 to 1,000 times in Russia.

"We need to make astronauts' operational moves habitual," said Chen Shanguang, head of the training center for Chinese astronauts.

"Manual control is the back-up measures for robotic control; it will be safer with human participation," Chen added.