In June, four volunteers began to simulate the experience of living in a sealed space capsule for 180 days. Well, they're half-way through their experiment at Shenzhen’s Southern Research Institute of Space Technology, and to celebrate they were able to call their families and make 3D-printed mooncakes for the Mid-autumn festival.

The 370-square-meter capsule is made out of six giant boxes with no simulation of weightlessness. Vegetables, fruits and various crops are cultivated in a tank to ensure a constant food and water supply. The volunteers are trying to simulate a journey to Mars, which is ultimately part of China's space program.