China will send its third human space mission into orbit Thursday on a flight that is slated to include the emergent space program's first spacewalk this weekend, officials announced Wednesday.

The 191-foot-tall Long March 2F rocket, topped with the Shenzhou 7 spacecraft, is set for blast off at 1307 GMT (9:07 a.m. EDT) Thursday. It will be Thursday night at the Jiuquan launch site in northwestern China.

Engineers began loading explosive and toxic hypergolic propellants Wednesday into the rocket's two core stages and four strap-on boosters. The launcher rolled out to the launch pad Saturday.

The rocket will release Shenzhou 7 about 10 minutes after liftoff. The ship will later use its own engines to reach a circular orbit about 213 miles high.

Astronauts Zhai Zhigang, Liu Boming and Jing Haipeng will crawl into Shenzhou 7 a few hours before launch Thursday. The crew, all 42-year-old Chinese military pilots, participated in a brief press conference Wednesday with reporters at Jiuquan.

"I'm confident that we can fulfill our tasks," Liu said. "I hope that (everyone) will see that Chinese astronauts are among the best in the world."

Chinese officials did not identify which astronaut would step outside for the spacewalk, but earlier reports indicated Zhai had been tapped for the job.

Zhai, also the mission's commander, trained as a backup for the Shenzhou 5 and Shenzhou 6 missions in 2003 and 2005. Liu and Jing were also finalists to fly on Shenzhou 6.

"From Shenzhou 5, 6 and 7, it's not just a change of numbers," Zhai said. "Shenzhou 7 represents a breakthrough in the Chinese space industry. It is of historical significance and I feel very honored to be able to participate in this flight."

Zhai commands a crew of three space rookies. Both astronauts that flew on the five-day Shenzhou 6 mission are backups on Shenzhou 7, according to state media reports.

"This is the third time for me to enter this fall and I should say that I feel more calm and composed than before, but also I feel a little more sense of responsibility on me," Zhai said.

The spacewalker will be accompanied by another crew member in the orbital module, which will act as an airlock during the depressurization and pressurization processes. Another astronaut will remain in the landing capsule.

"When one of us goes for the spacewalk, then there will be one who stays inside the (orbital) capsule," Liu said. "The two that stay back will support the one who conducts the spacewalk."

The lead spacewalker will don a new Chinese Feitian spacesuit and the other EVA crew member will wear an Orlan suit provided by Russia, according to Wang Zhaoyao, deputy director of China's manned space program.

China spent about four years developing the Feitian suit to provide critical life support systems for spacewalkers. The unit will also shield astronauts from orbital debris and radiation.

Chinese officials deployed nine tracking ships and 30 aircraft to stay in contact with Shenzhou 7 during the spacewalk, Wang said.

The astronauts will also deploy a small satellite from the ship and communications tests through a tracking and data relay satellite launched earlier this year.

The mission will cap years of training, including generic instruction and mission-specific training.

"We experienced tremendous pressures, but we were determined to work together to overcome all the difficulties," Jing said.

The crew trained for the spacewalk in a voluminous water tank similar to facilities in the United States and Russia. The water helps simulate weightless conditions that will be encountered in space.

"The weightless situation will be very different once we're in space, particularly from when we were in water because we have to fight against the weight in the water in our training," Liu said.

Plans call for Shenzhou 7 to spend at least three days in orbit before parachuting to a landing in Inner Mongolia as early as Sunday.