Speaking to mission control half an hour after blast-off, the lieutenant colonel in the People's Liberation Army said he was feeling good and the flight was going well, the official Xinhua news agency said.

"I feel good, see you tomorrow," Yang was quoted as saying.

Born in 1965, Yang comes from a relatively well-to-do family in Saizhong county in northeast China's Liaoning province. His father worked as an economist and his mother was a teacher, according to Chinese media reports.

Yang became an air force fighter pilot in 1983 and has 1,350 hours of flight experience. Ten years ago, he was chosen to undergo training to be an astronaut. Since then, Yang has devoted much of his time to training for the mission he began on Wednesday.

His training included spending a week in Russia to learn to adapt to weightlessness, Yang said in an interview to the China Central Television station.

Secrecy was a watchword for the program and, abiding by strict military guidelines, Yang was forbidden from talking about his work with his wife of 13 years, Zhang Yumei, and their eight-year-old son.

Yang and his family now live in the Jiuquan Satellite Launch Center, nicknamed "space city," in northwestern China's Gansu province. His wife, who is also in the military, works in the launch center, reports said.

Contact with the outside world was strictly minimized to an extent that even on rare visits to Liaoning province to see his parents Yang did not venture outside into town.

Yang was selected as a finalist from a pool of 14 top fighter pilots training to be astronauts. He beat out two other finalists, Zhai Zhigang and Nie Haisheng, partly because he showed a calm mental state during psychological tests, state media said.

His trainers and teammates describe him as "being very devoted to his work," the Xinhua website said.

As a child, Yang loved exercise and sports, including swimming and skating and frequently played outside.

He was in excellent health and rarely became sick, his elder sister told Chinese media. Yang's grades in school were average, but his grades in science courses were excellent, his sister said. He loved playing on the computer and tinkering with electronic goods.

His current salary is nearly 10,000 yuan (1,204 US dollars), part of which he regularly sends to his parents. Ironically, his salary is lower than that of a civilian pilot, New Express said.

SPACE.WIRE