In 2011, Congress ruled that China is not allowed on the International Space Station because of "national security" concerns. Undeterred, the People's Republic decided to build its own.

Tiangong-1, which launched in 2011, was the first step in that direction. The unmanned prototype served as a practice for docking spacecraft, and played host to a short manned mission. Now China's ready for part 2: sending astronauts to live in space for the longer term.

Tiangong-2 will launch from China's Gobi Desert at 10:04 p.m. local time on Thursday. A Long March 2F rocket will carry it into orbit 244 miles above the Earth. Then, in October, a crew of two astronauts will travel to the 34-foot-long lab and live there for 30 days.