This story was updated at 8:05 a.m. EDT.
While some details of China's second manned spaceflight have emerged, still others remain a mystery as the clock ticks down toward an Oct. 13 launch.
Two Chinese astronauts are expected to rocket into space aboard their Shenzhou 6 spacecraft when their Long March 2F rocket lifts off, but who those pilots will be is unclear.
"We still don't have a good sense as to who this new crop of astronauts are," said China space specialist Dean Cheng, with the CNA Corp. in Arlington, Virginia, in an interview. "That is the basis for Shenzhou 6's crew."
China has reportedly trained 14 fighter pilots, split into two-person teams, to serve as astronauts, though at least one will not be making the next space trip.
"I will not take this mission," said Chinese astronaut Yang Liwei - who flew aboard the country's first manned spaceflight Shenzhou 5 - during a space exhibition in Nanjing this month, China's Xinhua news agency reported.
Yang reportedly explained that he wanted to allow China's other astronauts - also known as 'taikonauts' from the Chinese word 'taikong' - an opportunity to gain experience, but the public admission was not surprising, experts said.
"I think we knew for awhile that Yang Liwei will not be a part of the next mission," Cheng said.
Yang launched into space, and into China history books, on Oct. 15, 2003. Riding aboard Shenzhou 5, Yang orbited the Earth 14 times in 21 ? hours before returning safely. The astronaut - then a lieutenant colonel in China's People's Liberation Army- was promoted to full colonel after his flight and is set to appear in a charity movie to raise funds for children in need.
The Shenzhou 6 mission is slated to last five days, or 119 hours, and mark the first time Chinese astronauts leave their Shenzhou craft's flight module and enter its experiment-filled orbital module, state media has reported. According to the Chinese newspaper People's Daily Online, Shenzhou 6 will launch between Oct. 13 and Oct. 17 and the spacecraft has already arrived at China's Jiuquan Launch Center in the Gobi Desert.
While Yang will not ride aboard that flight, whether or not his two Shenzhou 5 alternates - Zhai Zhigang and Nie Haisheng, according to a Associated Press report - are still in the running is unclear. Days before Yang's launch aboard Shenzhou 5, Chinese space officials had winnowed the flight pool down to the three astronauts.
"When they tell us, as a matter of course, who's in the [astronaut] class, with a little more than a headshot and the comment that their ex-fighter pilots, that'll be a sign of loosening up," Cheng said.
Yang said Shenzhou 6's flight will be noticeably more comfortable than his, featuring heated food, sleeping bags and sanitary equipment to meet all crew needs.
"One of my questions is how do they go to the bathroom [aboard Shenzhou craft] and whether or not the Chinese came up with a different solutions than the Russians," Cheng said.
China's Shenzhou spacecraft are based on Russia's extremely successful Soyuz spacecraft, but carry extensive modifications and changes by Chinese vehicle designers.
As more details of Shenzhou 6's flight are released, the flight's importance to the country and its China National Space Agency (CNSA) come to light.
According to earlier state media reports, Shenzhou 6 will launch in mid-October after China's National Day festivities which run from Oct.1-7. The flight's proximity to a national holiday highlights its importance, but CNSA limits the potential damage that a failure could inflict by waiting until after the festivities, Cheng said, adding that space officials would likely wait until after Oct. 10 - which is Taiwan's National Day - to launch Shenzhou 6.
"Launching and recovering in and around National Day has some political potential, though there is both an upside and a downside," he added. "This is a very prominent event and is going to have lots of media coverage."
Last week, state news media reported that China Central Television (CCTV) will carry Shenzhou 6's launch live and was soliciting advertisers for the upcoming space shot.
Commercial costs for the new advertisement spots range from $316,420 (2.56 million yuan) for five-second slots up to $1.05 million (8.56 million yuan) for a 30-second slot, according to the Beijing Modern Commercial Daily.
China officials initially refused to broadcast Shenzhou 5's launch live, though it was replayed after liftoff.
"I hope they do broadcast it live," Cheng said of the upcoming launch, adding that he expects there will likely be a 15-second delay in the broadcast.
Meanwhile, reports of China's construction of a new Shanghai space center, lunar exploration plans and space station goals - Shenzhou orbital modules can remain in space for longer periods than the flight modules - give shape to the country's future exploration plans.
"I think the larger program has become less tight-lipped," Cheng said. "We're actually getting a sense of a 10-year plan."
Chinese state media reported this month that the country's first female astronaut candidates - 35 women between 17 and 20-years-old in age - have begun a four-year university program coupled with science and flight instruction to prepare them for spaceflight.
There have also been some hints from Chinese space officials that by Shenzhou 7, Chinese astronauts will conduct the country's first spacewalk, with a docking test slated for Shenzhou 8, Chen said.
"I think that is a sign of willingness on the part of the CNSA to take a little bit of risk," Cheng said. "To say, 'Okay, we do need to build up a little of an expectation here.'"
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