China accomplishes its first spacewalk
BY STEPHEN CLARK
Posted: September 27, 2008
A pair of Chinese astronauts suited up and floated through the hatch of the Shenzhou 7 spacecraft Saturday for a dramatic 14-minute excursion in space, completing China's historic first spacewalk.
Zhai Zhigang, the 41-year-old commander of the mission, exited the ship through a 33-inch hatch on the orbital module at the forward end of Shenzhou 7. Zhai cranked open the hatch and floated outside at about 0840 GMT (4:40 a.m. EDT) Saturday.
Officials stationed at mission control in Beijing erupted in applause when Zhai emerged from the capsule.
"I am here greeting the Chinese people and people of the whole world," Zhai said has he floated more than 200 miles above the planet.
Liu Boming assisted Zhai in the spacewalk, crawling halfway through the hatch to hand Zhai a Chinese flag.
Cameras inside and outside the module beamed live video back to Earth throughout the spacewalk.
Both astronauts remained connected to the spacecraft with tethers and umbilical cables. Zhai maneuvered himself using handrails fastened to the outside of the module.
Zhai also retrieved an experiment package mounted on the exterior of Shenzhou 7.
Zhai closed the hatch at about 0900 GMT (5 a.m. EDT), and the module began repressurization a few minutes later as Shenzhou 7 reached orbital sunset.
Engineers said they marked the official start of the spacewalk at 0844 GMT (4:44 a.m. EDT). The spacewalk was officially completed at 0858 GMT (4:58 a.m. EDT), according to state-run television.
The spacewalk was timed to ensure continuous communications coverage through tracking ships, ground stations and a relay satellite in geosynchronous orbit. The craft passed over Africa, the Indian Ocean and Asia during the spacewalk.
Officials reported the orbital module reached normal atmospheric pressure at about 0950 GMT (5:50 a.m. EDT).
China hailed the spacewalk as a complete success and the astronauts said they felt well after the journey outside.
The orbital module was used as an airlock to depressurize and pressurize the craft's cabin before and after the spacewalk.
China Central Television provided live coverage of the spacewalk on its Chinese and English language channels.
Chinese President Hu Jintao visited ground controllers in Beijing during the spacewalk. Hu also witnessed Shenzhou 7's launch from the Jiuquan space center Thursday.
Zhai wore a domestic Feitian spacesuit for the extra-vehicular activity, or EVA. The suit weighs 265 pounds on Earth and costs about $4.4 million, according to state media reports.
Liu was protected by an Orlan spacesuit that China acquired from Russia.
The Feitian and Orlan suits have similar appearances, and China purchased three space-rated Orlan suits from Russia in 2004, according to Wang Zhaoyao, deputy director of China's manned space program.
Jing Haipeng, the third member of Shenzhou 7's crew, monitored the spacewalk from the entry module, which remained pressurized throughout the excursion.
The spacewalkers spent more than 30 minutes breathing pure oxygen to purge nitrogen from their bloodstreams. The "pre-breathe" process is similar to activities by U.S. and Russian astronauts before spacewalks.
The procedure reduces the chance of nitrogen bubbles forming in the blood of astronauts. This condition, known as the "bend," commonly afflicts deep sea divers.
The crew trained in a giant pool to prepare for the spacewalk. Water is the best way to simulate weightlessness and is used to train Russian and U.S. astronauts.
Saturday's breakthrough made China the third nation to complete a spacewalk after the former Soviet Union and the United States. Those countries' first spacewalks both occurred in 1965.
First came the Soviet Union. Cosmonaut Alexei Leonov floated through the hatch of the Voskhod 2 spacecraft on March 18, 1965, in a harrowing 12-minute spacewalk that was not announced until after it was completed.
Leonov's bulky spacesuit made it difficult for him to move, and the cord linking him with the spacecraft became twisted. After Leonov struggled to enter the airlock, he was forced to manually lower pressure inside his spacesuit, which had ballooned larger than its normal size.
Leonov finally closed the hatch and pressurized the airlock to end the first spacewalk in history.
Astronaut Ed White completed the first U.S. spacewalk less than three months later on June 3, 1965. White's 23-minute excursion outside the Gemini 4 went more smoothly than the Russian spacewalk.
White used a handheld gun-like thruster fueled by oxygen gas to help maneuver around the exterior of the two-man capsule.
Plans called for Shenzhou 7 to deploy a small monitoring satellite later Saturday. The craft could take pictures of Shenzhou 7 as it flies away from the ship.
Shenzhou 7 is expected to return to Earth Sunday with a fiery re-entry and landing in Inner Mongolia, a province in northern China.