BEIJING - CHINA this week launches its most ambitious space mission yet, a sign of rising confidence as Beijing cements its status as a space power and potential future competitor to the United States.

The Shenzhou 7 mission, to launch as early as Thursday, will be the first to carry a full complement of three astronauts, one of whom will perform China's first space walk, or EVA for 'extra-vehicular activity'. It is China's third manned mission.

The manoeuvre will help China master docking techniques needed for the construction of a space station, likely to be achieved initially by joining one Shenzhou orbiter to another.

The mission launches from the Jiuquan launch site in northwestern China. The lead astronaut, Zhai Zhigang, is expected to carry out the 40-minute spacewalk, which China will broadcast live.

'Shenzhou 7 is an incremental but important step forward,' said Dr Joan Johnson-Freese, an expert on the Chinese space program at the US Naval War College in Rhode Island.

Riding a wave of pride and patriotism after hosting the Olympics, China's communist leaders face few of the public doubts or budgetary pressures constraining such programs elsewhere.

That has allowed them to fuse political will and scientific gusto in a step-by-step process that could one day see Chinese astronauts landing on the moon.

Chinese space programmes are methodically moving forward in a 'very deliberate, graduated' manner, said Mr Charles Vick, a space analyst for the Washington think tank GlobalSecurity.org.

Beijing is accumulating the building blocks of a comprehensive program, demonstrating 'caution but confidence' as it gains on the US and other space powers, he said.

Future goals are believed to include an unmanned moon landing around 2012, a mission to return samples in 2015, and possibly a manned lunar mission by 2017 - three years ahead of the US target date for returning to the moon.

A manned lunar programme, although yet to be formally approved, is 'certainly the ultimate goal', Dr Johnson-Freese said.

First, Chinese scientists need to put the final touches on the new generation Long March 5 rocket capable of launching 25-tonne components for a space station or future lunar missions.

Once that happens, Dr Johnson-Freese said she expects further progress to come rapidly.

'When the new vehicle is ready, China wants to be ready too,' she said. Shenzhou craft are currently flung into space by a Long March 2F rocket, the workhorse of the Chinese fleet, with 66 consecutive successful launches.

The first manned Shenzhou mission in 2003 saw China join the United States and former Soviet Union as the only nations capable of launching astronauts into space.

From the start, China has focused squarely on high-payoff areas where it can match or exceed the achievements of others.

That garners new capabilities while maximising the political impact, something observers sometimes call 'techno-nationalism'.

All along, China has relied heavily on homegrown technology, partly out of necessity. China has trouble obtaining such technology abroad due to US and European bans and is not a participant in the International Space Station.

The Shenzhou ships closely resemble Russia's three-module Soyuz capsule, but have been completely re-engineered and enlarged.

China's team of 14 astronauts, sometimes called 'taikonauts' from the Chinese word for outer space, are trained at Chinese facilities.

Veteran chief designer Qi Faren says China's systems, while basic, have been carefully designed for safety and reliability.

'What we're proud of is that, although we're not the best, it's our own and its very Chinese,' Mr Qi, 75, said in an interview published in Monday's Beijing News. -- AP