BEIJING - China plans to launch its most ambitious space mission to date this week, cementing its status as a space power and potential future competitor to the United States.

The Shenzhou 7 mission, blasting off as early as Thursday, will be the first to carry a full complement of three astronauts, one of whom is expected to perform China's first space walk.

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 manned mission, China's third, will be launched 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.

Future goals of the Chinese program 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 U.S. target date for returning to the moon.

"Shenzhou 7 is an incremental but important step forward," said Joan Johnson-Freese, an expert on the Chinese space program at the U.S. 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.

A manned lunar program, although yet to be formally approved, is "certainly the ultimate goal," 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, 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 countries 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 maximizing 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 U.S. 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," Qi, 75, said in an interview published in Monday's Beijing News.