(GONG LEI)

Captain Xie Beizhen (front) and crew members Wang Minjuan (center) and Dong Chen walk out of the Moon Palace 1 capsule in Beijing on May 20, after spending 105 days in the closed lab.

It was China's first manned test of the Moon Palace 1, a 500-cubic-meter module that is the country's first bio-regenerative life-support base, and also the world's third largest.

During the experiment, the volunteers ate only laboratory-grown plants and insects.