As officials prepared for tonight's return of the Shenzhou IV spacecraft, the nation's top astronaut trainer said China's training programme was as good as those in the United States and Russia. 'The training of Chinese astronauts is right on schedule,' Su Shuangning told Xinhua. '[We] are ready to send well-qualified astronauts who can represent the Chinese people into space anytime.' Mr Su's remarks came as the country awaited the descent of the unmanned Shenzhou IV to earth today. Xinhua reported the craft would probably land in Inner Mongolia at dusk. Launched last Sunday in Gansu province, Shenzhou IV is expected to be the nation's last unmanned space flight. Mainland scientists and experts have said the next space flight - which will probably take place in the second half of this year - will carry astronauts. Mr Su said that like their US and Russian counterparts, Chinese astronauts had been chosen from a select group of top fighter pilots. They are an average height of 170cm and weigh about 65kg. 'According to Su Shuangning, the selection ratio of Chinese astronauts is about one in 100. This is basically the same as that in the US and Russia,' Xinhua said. 'I can guarantee that the astronauts have the ability to successfully perform their mission in space. They are all brave men who we are very proud of. They all want to be the first batch of Chinese astronauts to travel in space.' According to Mr Su, all potential astronauts had gone through rigorous and exhaustive physical, physiological and mental tests and training. The astronauts' physical training included endurance tests in a low-oxygen environment. Other training included studies in aeronautical physics, rocket engineering and medicine and instruction in operating and piloting the spacecraft. As the space capsule could accommodate only two or three people, Mr Su said the astronauts had been trained to perform all tasks. He added that they had also received extensive training in survival skills. Such instruction was necessary because of the unpredictability of spacecraft landings, and the astronauts had to be able to fend for themselves if the vessel landed in the sea or desert areas outside the landing zone.