Inside Space City

If you stumbled into Space City, you probably wouldn't realize what it was.

The sprawling complex in the north west of Beijing shares the same nondescript character of government compounds throughout China.

But look closer. Guard posts over here; military sentries checking IDs over there.

This is no ordinary facility. Space City is home to the Chinese government's most ambitious and expensive mega-project ever. They've dubbed it "Project 921," the manned-space program.

And foreign journalists are almost never let in.

After more than a year of phone calls and faxes, here we are, inside the simulation room of the astronaut training center.

The astronauts stride into the room according to rank: Nie Haisheng, Zhang Xiaoguang and Wang Yaping.

They're three of China's best-known astronauts and the crew of the 2013 Shenzhou-10 mission, China's longest manned spaceflight yet.

They're roughly the same height and build in their blue jumpsuits and black military boots.

That's no accident. Chinese astronauts are all People's Liberation Army pilots and officers, they have university degrees, they are Communist Party members. And they need to be around the same height and under a certain weight.

You don't need to be superhuman to be an astronaut, says Commander Nie.

"We are just ordinary people," he says, "But, yes, certain aspects make us more suitable to fly space missions."

China's space program was first announced in the early 1970s, but the chaos of the Cultural Revolution stopped it in its tracks.

The program accelerated again in the early 1990s and space administrators picked two classes of astronauts in 1998 and 2010.

All of the crew of the 15-day Shenzhou-10 mission was passed over for missions at least once.

"When I wasn't selected for a mission, there was nothing I could do about it, so I just kept looking forward," says Zhang.

Zhang is the self-described joker of the group, able to lighten the mood during high-pressure situations. Still, he says he had to live through years of disappointments.

"I trained in this simulator for 15 years and I was in space for 15 days. So literally a day in space was a result of a year of training on the ground."

Perhaps the most famous of the group is Wang Yaping. She conducted a live space lecture for 60 million students across China during the mission.

"I remember, I watched the launch of the first Chinese astronaut into space with my fellow pilots," says Wang, who flew a transport plane for the PLA.

"I saw the fireball come out of the rocket and a thought just popped into my head: 'The first Chinese man just flew into space. When will the first female astronaut from China get there?'"

After years of training, you would think that it is all about the mission. But what happens when the space lectures and experiments are over?

"We really enjoyed the zero gravity situation in our spare time," says Wang. "It allowed us to practice tai chi upside down, it allowed us to float around like fish."