As China prepares to launch its fourth unpiloted Shenzhou spacecraft, Western observers continue to speculate about the timing, mission parameters and the crew make-up of that country's first ever manned space mission scheduled for next year.

It is currently believed that a dozen or more Shenzhou pilots are undergoing extensive training and evaluation.

While still guarded in discussing details, Chinese space authorities are clearly laying out an extensive campaign of human space exploits, including the creation of a space station.

At present, the unmanned Shenzhou 4 is being readied for flight, along with its Long March 2F booster at the Jiuquan Satellite Launching Center of Gansu Province in China. According to government news services, the flight could take place in September.

"We have intensified development of the Shenzhou 4 and its carrier rocket, which we plan to launch sometime in the remaining months of the year," said Zhang Qingwei, president of China Aerospace Science and Technology Corporation (CASC). This Beijing-based industrial firm is heavily involved in the country's space effort.

CASC has about 230,000 employees, 30 percent of which are technicians, engineers, and researchers; 40,000 are professors and senior engineers, according to the Center for Nonproliferation Studies at the Monterey Institute of International Studies in California.

Other sources within China's space program, however, have also stated the next Shenzhou mission might not occur until early next year. China's Xinhua News Agency, for instance, noted August 22 that a deadline had been set for lofting Shenzhou 4. The news organization quoted an unnamed "expert" that the ship would fly by next January 10, at the latest.

The Xinhua News Agency reported CASC's Zhang as saying that China is pushing forward in spaceship docking, space labs, and deep space exploration.

Furthermore, Zhang stated that his organization is expediting the creation of a new family of launch vehicles, to be flying before 2005.

Depending on the success of Shenzhou 4, China is likely to loft its first crew into Earth orbit next year.

"Whenever Shenzhou 4 does go, barring a major flight failure, I expect that Shenzhou 5 will carry the first Chinese crew," reports noted space expert, Phillip Clark, head of the Molniya Space Consultancy in the United Kingdom.

"The only real question is whether there will be two or three people on board," Clark told SPACE.com.

That first piloted space mission should come in the first six months of next year, Clark said. The Chinese have already said the names of their first space travelers will be announced shortly before the Shenzhou 5 liftoff, suggesting they'll be onboard that craft, he added.

One mystery is what's up with a Shenzhou 3 orbital module that is still circling Earth.

That spacecraft segment has been in Earth orbit for months, maneuvering on several occasions. It was left in space while the Shenzhou 3 descent module parachuted to Earth April 1.

One future prospect is that the Shenzhou 4 may carry out rendezvous practice with the still-in-space orbital module.

"The Shenzhou 3 orbital module looks like it will be at the right 31-circuits repeater altitude in September, but the question is whether Shenzhou 4 will be ready to go," Clark said.

There was a report earlier this year, Clark added, that the next Shenzhou capsule would end its flight with an ocean landing, presumably in the Pacific. "This would prove that the descent module could survive a water landing as a back-up, although coming down on terra firma will be the prime recovery mode," he said.

Looking into the future, Clark thinks it possible that piloted Shenzhou missions could grace space at a pace of a couple per year. Perhaps a docking between a Shenzhou 7 and Shenzhou 8 might be on tap for early 2004, he speculates.

However, one pacing item is China's need for a larger booster. Given a heavy-lifter class rocket, a small orbital laboratory may be launched to which Chinese crews could visit, Clark said.

Another China space watcher sees it somewhat differently.

Charles Vick, Chief, Space Policy Division, of the Federation Of American Scientists in Washington, D.C., thinks a Shenzhou 4 rendezvous test might not be in the cards.

"I believe that the potential near-rendezvous test with Shenzhou 3's orbital module is still possible but the present indications possibly suggest to the contrary," Vick said. He believes that China may take a much more conservative ramp up to their first manned flight attempt next year with the Shenzhou 5 spacecraft.

"Taking small steps is the rule of safety at this point," Vick added, to assure to the greatest extent possible that a manned mission is successful, he said.

"Depending on what they actually do with this possible last unmanned flight test, the Shenzhou 4 mission could indeed be the prelude to China's first manned flight with Shenzhou 5 in the spring through fall 2003," Vick said.

"In the final analysis this is strictly dependent upon the upcoming flight test results which could just as easily reveal unforeseen problems, forcing planning decision changes. I wait patiently for this flight test which should come sooner than later," Vick concluded.

"China's manned space program is like China's desire to host the Olympics - it's all about prestige," said Phillip Saunders, Director of the East Asia Nonproliferation Program at the Center for Nonproliferation Studies. The Center is located at the Monterey Institute of International Studies in Monterey, California.

"The U.S. and Russia are the only countries with an independent manned space program. By joining the space club, China is staking a symbolic claim to being in the same league. This is the main reason the Chinese government has been willing to invest resources in the manned space program. This also leads China to downplay the extent and importance of Russian assistance to China's manned space program.

Saunders said that, from the Center's perspective, one key area of interest is the impact of the manned space program on China's strategic modernization efforts and on potential military uses of space.

Although the manned program attracts more resources to China's overall space effort, Saunders said, it also diverts resources and scarce engineering talent away from areas with direct military applications.

"While China will certainly learn skills and technologies from the manned space program -- such as improved maneuvering, control, and tracking capabilities -- on balance the manned space program probably slows down Chinese efforts to modernize strategic missiles and to develop a potential space warfare capability," Saunders said.