China's joint assembly of the unmanned spacecraft Shenzhou-8 and the prototype space lab Tiangong-1 at 12:04 p.m. Tuesday Beijing Time carried out orbit maintenance for the second time, according to the mission's control center.

While on Monday China completed its second space docking test during which the spacecraft Shenzhou-8 disengaged from Tiangong-1 module after an around 12-day flight together and then re-docked with it.

Shenzhou-8, launched on November 1, rendezvoused and docked with the target orbiter Tiangong-1 on November 3 in an orbit 343 km above Earth, marking China's first space docking a success. Tiangong-1 has been in orbit since its launch on September 29.

The coupled spacecraft performed its initial orbit maintenance successfully on November 4, and Tuesday's maintenance is their last such operation before Shenzhou-8's return to Earth, according to Beijing Aerospace Control Center (BACC), which is in command of the mission.

Shenzhou-8 is set to return to Earth Thursday evening, Wu Ping, spokeswoman for China's manned space program, said earlier.

(Xinhua News Agency November 15, 2011)