Tiangong 1, or Heavenly Palace, is scheduled to blast off between 9:16 p.m. and 9:31 p.m. from the Jiuquan Satellite Launch Center in nothwest China's Gansu Province.

The launch will mark the start of China's first spacecraft rendezvous and docking mission.

The unmanned spacecraft will be sent into an orbit some 350 km above Earth for in-orbit testing.

Experts will need some 40 minutes after launch to judge whether Tiangong 1 is functioning properly. This is because when it enters orbit and deploys its solar panel, some 10 minutes after the launch, it will be on the dark side of Earth. It will be another 30 minutes or so before ground control can gauge if all systems are working.

The technicalities behind the rendezvous and docking maneuvers, vital procedures for any space station program.

According to the plan, Tiangong 1 will descend to a 343-km orbit days prior to the launch of the unmanned Shenzhou-8 spaceship in early November.

Two days after the Shenzhou-8 launch, the two craft will rendezvous and dock for the first time. They will stay docked for 12 days before decoupling. A second rendezvous and docking will be conducted some time later this year.

Shenzhou-8 will then return to Earth somewhere in north China's Inner Mongolia Autonomous Region.

Tiangong 1 will stay in orbit for two more rendezvous and docking missions next year. At least one of these missions will be manned

According to the manned space program, China will build its space lab before 2016, and assemble its 60-ton space station around 2020.

(China Daily September 29, 2011)