Astronaut which describes it as "a hybrid of the Chinese term "taikong" (space) and the Greek "naut" (sailor)"; the term became more common in 2003 when China sent its first astronaut Yang Liwei into space aboard the "Shenzhou 5" spacecraft. This is the term used by Xinhua News Agency in the English version of the Chinese "People's Daily" since the advent of the Chinese space program. The origin of the term is unclear; as early as May 1998, Chiew Lee Yih () from Malaysia, used it in newsgroups. With the rise of space tourism, NASA and the Russian Federal Space Agency
Astronaut training the ISS. The Tsukuba Space Center also includes medical facilities for assessing suitability of candidates, an isolation chamber for simulating some of the mental and emotional stressors of long duration spaceflight, and a hypobaric chamber for training in hull breach or Life Support System failure scenarios resulting in a reduction or loss of air pressure. Although official detail of the selection process for the Shenzhou program is not available, what is known is that candidates are chosen by the Chinese National Space Administration from the Chinese air force and must be between 25 and 30 years of age, with a