China is set to launch an experimental, recoverable moon orbiter before the end of the year, according to the nation's space agency.

The orbiter, which aims to test the technologies that are vital for the Chang'e-5 mission, will be launched into lunar orbit at an escape velocity of 11.2 km per second, said the State Administration of Science, Technology and Industry for National Defense. The spacecraft will also return to Earth.

The craft was transported to Xichang in Sichuan province on Sunday and then taken to the Xichang Satellite Launch Center, according to a statement from the administration.

The orbiter is one of the test models for China's new lunar probe Chang'e-5, whose mission will be to land on the moon, collect samples and return to Earth.

China launched the Chang'e-3 probe with the nation's first moon rover, Yutu, in December. The probe successfully landed on the moon. Yutu has outlived its designed lifespan of three months and is still performing scientific operations despite mechanical control problems reported in January.

The Chang'e-3 mission is part of the second phase of China's current lunar program that includes orbiting, landing and returning to Earth. It follows the successful Chang'e-1 mission in 2007 and Chang'e-2 in 2010.

As the backup probe of Chang'e-3, Chang'e-4 will be adapted to verify the technologies for Chang'e-5.

The more sophisticated Chang'e-5 requires technological breakthroughs in moon surface takeoff, sampling encapsulation, rendezvous and docking in lunar orbit, and high-speed Earth re-entry, the administration said.

Chinese scientists have begun research for the most difficult part of the mission.

Wang Pengji, a space expert at the China Academy of Space Technology, said, "We have begun to study how the Chang'e-5 will blast off from the moon and dock with the orbiting re-entry capsule."

The Chang'e-5 probe is set to be launched around 2018, and will be taken to space by the nation's first heavy-lift rocket, the Long March-5, in the new launch center in Wenchang in the island province of Hainan.

Development of the Long March-5 and construction of the Wenchang launch center are progressing well, according to Liu Jianzhong, deputy designer of the lunar program's rocket system.

Zhao Lei contributed tothis story.

(China Daily USA 08/12/2014 page4)