Zhai, 55, was the first Chinese astronaut to conduct a spacewalk — he floated out of the Shenzhou VII spacecraft for about 15 minutes during its three-day mission in September 2008.

That short adventure made China the third nation in the world, following the former Soviet Union and the United States, capable of independently conducting a spacewalk.

The Shenzhou XIII mission was launched on Oct 16 by a Long March 2F carrier rocket that blasted off from the Jiuquan Satellite Launch Center in northwestern China's Gobi Desert, with the crew soon entering the Tiangong space station, whose name means Heavenly Palace. They are scheduled to spend six months working in the station, making it China's longest space mission.

Before the spacewalk, they had moved living and work materials from the Tianzhou 2 and 3 cargo spaceships to the station's core module, named Tianhe, or Harmony of Heavens, tested their extravehicular suits, and conducted training on robotic arm control and medical aid, according to the manned space agency.

Their peers in the Shenzhou XII mission, which lasted three months and concluded in mid-September, performed two spacewalks.