A staff worker monitors the status of volunteers in Yuegong-1 at Beihang University in Beijing, capital of China, July 9, 2017. The second volunteer group, two men and two women, replaced the first group and stepped into the simulated space "cabin" Yuegong-1 on Sunday. They will stay there for 200 days. The experiment, code-named "Yuegong-365," is Beihang's second attempt to see how the Bioregenerative Life Support System (BLSS) works in a moon-like environment. (Xinhua/Zhang Chenlin)
