China's bold plan to land an unmanned spaceship on the moon before returning to Earth has moved another step forward with a test craft shifting into lunar orbit to conduct further tests.

The service module of a lunar orbiter that flew back to Earth in November had been sitting in a position that brought in into sync with Earth's orbit, known as the second Lagrange point. It had separated from the orbiter in November.

China plans to land a spacecraft christened Chang'e 5 on the moon in 2017 and have it collect at least 2 kilograms (4 pounds) of rock and soil samples before returning to Earth.

If successful, that would make China only the third country after the United States and Russia to meet such a challenge.