Yang's promotion to full colonel was approved several weeks ago, but his superiors did not tell him until after he returned Thursday from his 21 1/2-hour space flight, Xinhua said.

"The promotion decision was made for his excellent performance as a member of the team during recent years," the agency said.

However, it said, ``His superiors decided not to inform Yang of the decision as they thought it might affect his mood as the manned space mission was approaching.''

Yang's identity was not disclosed by the secretive, military-linked space program until after his Shenzhou 5 capsule blasted off Wednesday from a base in China's desert northwest.

But since then, he has been the subject of intense publicity by the communist government's propaganda machine, which lauds him on television and in newspapers as a symbol of the successes of China's military and ruling party.

Yang "became an instant hero in China" following his flight, Xinhua said.

Yang, 38, was flown back to Beijing hours after his touchdown Thursday in China's northern grasslands, though there has been no sign yet when he might appear in public.

State television has repeatedly shown scenes of Yang in training, working in his space capsule and talking to his wife and 8-year-old son from orbit.

"Yang had a happy and tranquil childhood," Xinhua said. "He was intelligent as a child and a good team leader of his playmates, his parents recalled. Yang won many prizes in math competitions.''

The report said Yang was a straight-A student at military college after joining the air force of the People's Liberation Army in 1983. It said that after becoming a fighter pilot, he ``rated the elite'' of his military division.

Yang was one of three finalists for the space flight. They were part of a 14-member astronaut corps, picked from among 1,500 military pilots.

Su Shuangning, director-general of the astronaut program, described Yang as sober-minded and with a ``superb capability for self-control," Xinhua said.

Also Monday, Xinhua added to disclosures by the newly confident space program about its technology, reporting that Yang was aided by an "electronic secretary" with an artificial voice.

The machine recorded the speed, altitude and other data about Yang's flight and could give ``short, clear ... mezzo-soprano voice instructions'' if anything was out of the ordinary, Xinhua said. It did not say whether Yang received any such alerts in flight.

Space program officials said last week that China intends to launch its next Shenzhou flight within two years and plans eventually to have a permanently manned space station.