As the nation held its collective breath, China's first astronaut, Yang Liwei, floated back to the motherland, having orbited Earth 14 times in Shenzhou 5, or Divine Capsule. It was October 2003, and the national broadcaster carried live coverage of the momentous event, from Yang's famous pleasantries in space – "I feel good" – to the instant the capsule door opened to reveal the pale but smiling face of a hero, offering irrefutable evidence that China's maiden manned space voyage had gone off without a hitch. Or had it?

In a lecture he gave to a group of journalism students last month, a top official at Xinhua, the state news agency, said the mission was not so picture perfect. The official, Xia Lin, described how a design flaw had exposed the astronaut to excessive G-force pressure during re-entry, splitting his lip and drenching his face in blood. Startled but undaunted, workers quickly mopped up the blood, strapped him back in his seat and shut the door. Then, with cameras rolling, the cabin door swung open again, revealing an unblemished moment of triumph.

The content of Xia's speech, transcribed and posted online by someone who attended the lecture at Tianjin Foreign Studies University, has become a sensation, providing the Chinese a rare insight into how their news is stage-managed.

The speech was intended to help budding journalists understand Xinhua's dual mission: to give Chinese leaders a fast and accurate picture of current events and to deftly manipulate that picture for the public to ensure social harmony, and by extension, the Communist party's hold on power. Xia's journalism lecture included other examples of Xinhua's work, notably coverage of ethnic rioting in the far west of China last summer that left nearly 200 people dead.

Xia explained how Xinhua concealed the true horror of the unrest for fear that it would set off violence beyond Urumqi, the capital of the Xinjiang region. Rioters burned bus passengers alive, he told the class, raped women and decapitated children.