BEIJING - China's troubled lunar rover Yutu is still alive and functional after more than five months on the moon, a lunar program official said Wednesday.

Its functionality has been weakened considerably by the bitterly cold lunar nights after the rover experienced a "mechanical control abnormality" in January, said Li Benzheng, deputy commander-in-chief of China's lunar program.

The rover can still send data back to Earth via China's lunar probe Chang'e-3 which carried Yutu to the moon, he said, but its wheels are no longer functioning nor are the solar panel designed for thermal insulation during lunar nights.

"With each lunar night, the functionality of Yutu is yet again weakened," Li said.