Here are biographical details of the three Chinese astronauts due to blast off Thursday for the country's third manned space mission, including a first space walk.

The details are impossible to verify as all China's astronauts are military personnel and their files are in the possession of the armed forces.

China has treated all its space heroes as role models, especially for the young, and state media invariably put them in a favourable light.

Zhai Zhigang

Zhai, born in October 1966, is expected to make history as China's first man to walk in space. Described by those close to him as introverted and loyal, he grew up in a poor family in northeast Heliongjiang province.

His father was bedridden for years, leaving his mother to support their family by selling watermelon seeds, and Zhai worked after school to earn money.

He wanted to drop out of school to work full time, but his mother, who was illiterate, insisted all six children should get a decent education.

The air force colonel was one of 12 men named among China's first group of astronauts in January 1998.

Zhai was shortlisted to go into space on Shenzhou V, China's first manned space flight, and Shenzhou VI, but ended up serving as a back-up crew member for both flights.

His hobbies are said to include ballroom dancing, calligraphy, and playing video games with his son. His wife Zhang Shujing works at the food research centre for astronauts.

Liu Boming

Liu, born in September 1966, is expected to be Zhai's back-up for the space walk. His intelligence as a boy earned him the nickname "Little Zhuge" after Zhuge Liang, one of ancient China's greatest strategists and the hero of the John Woo film "Red Cliff."

The second of six children, he signed up for military service to avoid being a financial burden on his poor rural family.

He and Zhai have a lot in common. They were born in Heilongjiang, escaped poverty by joining the air force in 1985 and trained together among China's group of pioneer astronauts.

Liu was a reserve crew member for Shenzhou VI, China's second manned space flight, in 2005.

Liu's mother died of a heart attack while he was training for Shenzhou V in 2003. He had six months of therapy to cope with his grief, his father said.

Jing Haipeng

Fellow astronauts call Jing, born in October 1966, the "Iron Forward" for his dominance on the basketball court.

He initially failed the physical on his first attempt to get into the air force academy, but tried again and was successful.

A year before being made an astronaut in 1998, the fighter pilot named his newborn son Yufei -- yu means space and fei means flying.

He was also on the back-up crew for Shenzhou VI.