This year marks the 20th anniversary of China's first manned space mission, with Yang Liwei becoming the first Chinese astronaut to go to space. Since then, another 19 astronauts have reached for the stars. The selection of the fourth generation of astronauts began in 2022 and is now in full swing. Experts revealed how tough the training is before astronauts can fly to space.

The human body is not designed for space life. Astronauts are faced with multiple challenges on a space mission. The changes in gravity can have an impact on their bodies. The sensation of confinement (封闭) living in a small spacecraft for months can damage their mental health. Emergencies during missions challenge their knowledge and ability to solve problems under huge pressure. So it's no wonder that astronauts have to meet extremely high standards and go through a tough training program.

To make sure that Chinese astronauts complete their missions and return to Earth safely, "Eight types, including over 200 subjects of training, were set," Huang Weifen, chief designer of the astronaut system for China's manned space project, told CCTV News. Apart from physical fitness training, it also includes basic scientific theories, psychological health, and mock (模拟) missions.

Among the training subjects, the most tiring one is underwater training. This training is designed for astronauts to adapt to the microgravity environment in space. According to Huang, astronauts stay underwater in suits weighing over 100 kilograms for six hours at a time. Water resistance (阻力) and the heavy suit make every move exhausting. "Nie Haisheng, one of the astronauts, once reported a two-kilogram loss in weight after one underwater training exercise," said Huang. Each astronaut receives training for at least three and a half years before having the chance to go to space.