Yang Liwei, China's 38-year-old first man in space, is scheduled to touch down somewhere in Inner Mongolia after covering half a million kilometers (310,000 miles), the Xinhua news agency said.

He can add his more than 21 hours spent in space to the 1,350 hours of flight experience he has clocked up as a fighter pilot, according to the agency.

The Shenzhou V lifted off from its Inner Mongolian launch pad at 9 amWednesday, making China the third country in the world to send a man into orbit after the former Soviet Union and the United States.

The re-entry process would begin while the Shenzhou was in the middle of its 14th and final orbit early Thursday morning, James Oberg, a 22-year veteran of the US National Aeronautics and Space Administration (NASA), said.

The spacecraft was expected to automatically fire its retro-rockets to begin re-entry when the Shenzhou V was over a Chinese tracking station in Namibia, Oberg told AFP.

"After firing the retro-rockets, the space ship should re-enter the earth's atmosphere over Pakistan early Thursday morning. It will be a spectacular show with a fireball lighting up the sky," Oberg said.

Besides having monitoring stations in China, Namibia and Pakistan, the Shenzhou was also being followed by four Chinese tracking ships -- two in the Pacific Ocean, one in the Atlantic Ocean and the other in the Indian Ocean.

Re-entry will be the most complicated task following the launch with the landing of the re-entry vehicle in Inner Mongolia dependent both on the precise firing of retro-rockets and the angle of re-entry of the capsule.

"Every second delay in firing the retro-rockets will mean that the landing will be pushed eight kilometers (five miles) eastward, so a 10 second delay could result in the Shenzhou landing 80 kilometers (50 miles) away from the landing site," he said.

In China's previous unmanned Shenzhou test flights, each of the capsules returned to the pre-set landing site and were immediately retrieved by ground crews, he said.

SPACE.WIRE