Thirty-six healthy male volunteers lay on beds with their heads low and feet high for 90 days for an experiment to simulate weightlessness that will pave the way for Chinese astronauts' long-term stay in space.

The number of people simultaneously participating in such an experiment was a world record, Li Yinghui, deputy chief designer for the astronaut system of China's manned space program, recently told the first China Space Science Assembly in Xiamen, east China's Fujian Province.

The Earth Star-2 experiment, conducted by the China Astronaut Research and Training Center, is preparation for China's space station, which is expected to be completed around 2022.

When the body is recumbent for a long time, fluid moves to the head and chest, and the leg bones and muscles are less active and stimulated, similar to the body changes of astronauts in space due to weightlessness, said Li.

"In the experiment, we can study cardiovascular dysfunction, bone loss, muscle atrophy, endocrine disorders and other medical problems under the conditions of weightlessness in space," she said.

"The experiment could provide scientific data on the impact of long-term weightlessness on the human body, and help us test the effectiveness of the protection measures for astronauts," Li said.