Chinese media coverage of the Shenzhou 7 mission is escalating as the launch date approaches. Before the end of September, China will launch its third manned space mission, and produce its first spacewalk.

We have been given snippets about emergency rescue drills and the impressive array of cameras that will monitor the flight.

Most of this is either predictable or reiterates previously known facts. But little has been said about one of the most important revelations in recent weeks. China is apparently preparing to select a second group of astronauts.

China formed its first group of astronauts for the Shenzhou program in 1998. The group consists of 14 men, all fighter pilots from the Chinese air force. There has been little insight into the overall dynamics of the astronaut corps. China guards its spacemen closely, even when they make international appearances.

Now, an article printed in Shanghai Daily quotes China's first astronaut, Yang Liwei, as a source on the claim. China Daily has also carried a similar story, quoting the pro-Beijing newspaper Wen Wei Po.

Combining the reports, and adding what we know of the currently planned missions, it would seem that China's original group of 14 spacemen will not have long to fly. Three of them will lift off soon on board Shenzhou 7.

In roughly two years, another three will probably launch on the Shenzhou 10 spacecraft, to rendezvous with the Shenzhou 8 and 9 space laboratory complex in orbit. China will probably try to squeeze in at least one more Shenzhou flight, probably to the Shenzhou 8 space laboratory, before the end of 2012.

After this, the original 14 will probably lose their status as active astronauts.

Both reports cite the age of the astronauts as a factor in their retirement, pointing out that all of the current astronauts are in their 40s. This is quite an unusual move for a modern space program. Much older astronauts are regularly launched into space by other nations.

It's possible that the conditions experienced on a Shenzhou mission are far more physically demanding than a Shuttle or Soyuz launch. Mention has been made of the high vibration levels experienced by Yang Liwei on his flight, along with claims that the rocket has since been improved to lessen them. But there's no shortage of older people who could deal with such conditions.

The reports suggest that the next group of astronauts will be smaller than the 14 in the original team. This is understandable. Given the slow pace of launches, China has probably found that it has more astronauts than it can fly.

Some of the first group will retire without a space mission under their belt. If some of the astronauts fly more than once, then as many as one third of the group could be unflown.

But what type of people will be selected? More of the same, if the reports are on target. China Daily states that the average age will be 30, and will be Air Force pilots.

There seems to be no mention of recruiting scientists, doctors or engineers, as other human spaceflight programs do.

No mention of recruiting women is made, although China could certainly tap them from its ranks of pilots.

If an age of 30 is the general threshold, then the second group of astronauts should be eligibile for flight for at least another 15 years. It will take roughly 4 to 5 years to train them.

The second group of astronauts will probably become crews for a larger Chinese space station, to be constructed at some time after 2012.

At this stage, it would seem that China has no plans to diversify its crews with international astronauts.

When will we know the identities of the new group? It will probably take at least another year. The Internet will fill with rumours of "phantom astronauts" who may or may not be real flight candidates. But media controls will probably remain tight, at least while training is underway.

Hopefully, China will eventually give us all more access to its next group of space travelers than its first.

Dr Morris Jones is the author of "When Men Walked on the Moon" and "The Adventure of Mars" now available through online bookstores. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email.