When they make it, China will become the third country in the world who is able to conduct extravehicular activity (EVA) in space following the former Soviet Union and the United States.
President Hu Jintao watched the historic moment at the launch center, joined by Chinese experts and other work staff.
Hu briefly met the trio taikonauts before they entered the spacecraft Thursday afternoon, wishing them "a complete success in this glorious and sacred mission".
"During the mission, you will carry out China's EVA with homemade EVA space suit, which is a great leap for China's space technology," said Hu.
Two taikonauts would enter the orbital module, where one would put on domestically-made spacesuit Feitian and leave the module to take back test samples loaded outside, said Zhou Jianping, chief designer of the country's manned space project.
The other would wear a Russian Orlan suit and stay in the depressurized cabin for support, said Zhou.
"We wish we could fly freely in space just like Feitian on the ancient Buddhist murals, so we gave this name to the homemade spacesuit," said Zhou.
Feitian, which literally means flying in the sky, is the name of a legendary Buddhist goddess.
Other tasks of the Shenzhou-7 crew include the release of a small monitoring satellite and a trial of the data relay of the satellite Tianlian-I.
If successful, the mission would be of great significance to the country's future plans to build a space lab and a space station, said Zhang Jianqi, deputy chief commander of the manned space project.
"China pursues the principle of making peaceful use of space in its exploration and development," Zhang told Xinhua, saying the country was willing to carry out various forms of international cooperation in space exploration.
The taikonauts, all 42 years old, are scheduled to land in the central region of north China's Inner Mongolia Autonomous Region in a re-entry module after their mission is completed.
