Jia Yang at the moon rover's desert test site in Gansu province. [Photo provided to China Daily]

Could Yutu survive the severe cold? "We thought the possibility was very low," says Jia.

"It's like feeling that a monster is going to swallow you, while your mind is very clear, but you cannot move. We'd done everything we could. There was nothing else. Maybe it was time to say goodbye," Jia says, falling into a long silence.

But Jia and the other developers were presented with a "miracle" when Yutu sent back signals after the "moon night" on Feb 12.

After that, they tried to fix Yutu's solar-panel mechanisms again, but failed.

Although Yutu accomplished its scientific and engineering goals, that mechanical failure is a source of regret.

"I have tried my best. The enlightenment gained from our trials is more precious than success," says Jia.

Jia was born in 1970, the year China sent its first satellite, Dongfanghong I, into orbit, and launched the country into space age. When he was 8, he read a book about the solar system and became obsessed with astronomy.

He entered the National University of Defense Technology, majoring in solid-fuel rocket engines, and got his master's and doctoral degrees at the China Academy of Space Technology.

He began work for CAST in 1995, as China's market economy began to boom. Many aerospace experts were lured to private or foreign-funded enterprises. A popular jingle at the time - "Making missiles earns less than selling tea eggs" - highlighted low salaries in the government sector.