Zhang Qingwei, president of China Aerospace Science and Technology Corp, made it clear the US incident will not upset China's applecart.

"China put into place its space program long ago, and it will stick to its schedule without being distracted," he told China Daily in an exclusive interview Thursday.

This is the first time since the Columbia tragedy on February 1 that China's space authority has explicitly promised to forge ahead with its plan of sending astronauts into orbit.

There has been no official announcement specifying when China will launch its first manned spacecraft before now.

"Technically, there is no direct link between China's manned space program and US missions, and China has developed an effective quality control system in rocket and spacecraft manufacturing, launching and scientific research," Zhang said.

Zhang's company is the main manufacturer of spacecraft and launch vehicles. It is also a chief participant in China's manned space program.

Zhang said the assessments from the previous four unmanned test space flights between November 1999 and January 2003 had basically given the go-ahead for China to proceed to manned missions.

He mentioned particularly the Shenzhou IV ("Divine Vessel" IV), which landed safely early last month after nearly seven days in orbit.

Space watchers said the completion of its successful voyage started a countdown for China to realize its ambitions of becoming the third country to put people into orbit -- after the former Soviet Union and the United States. But some had speculated the Columbia incident may slow China's progress in the field.

"Overall, the series of unmanned test flights were quite a success in that they proved our technological plans are good... and the various systems of China's manned project have coordinated well," Zhang said.

Qi Faren, chief designer of the Shenzhou spacecraft, said all tests and data involving the astronaut flight system in the last two test missions had met the required standards.

More unmanned test flights could help uncover and resolve potential problems with a space vessel and improve its reliability, space experts said.

But Zhang said he believed China can call it a day in terms of unmanned test flights, citing its achievements to date.

In fact, the Shenzhou IV craft was fully equipped for manned space flights, he said.

Qi said astronauts had trained in the spacecraft before its launch and scientists had eight contingency plans in place to ensure astronauts could escape safely in emergencies.

Zhang reiterated that China seeks an early breakthrough in its manned space program, which carries the nation's dreams.

The aerospace sector now has "zero tolerance" for glitches or deficiencies in the design and manufacture of carrier rockets and spacecraft, or in the operation of space vessels, he said.

The China-made Long March series of space vehicles have recorded 27 consecutively successful launches since October 1996.

Liu Zhusheng, leading designer of the carrier rocket system of China's manned space program, said the "Long March II F" rocket -- which was used to blast off four unmanned spacecrafts -- is on par with the best in the world in terms of reliability and safety.

In the United States, Theresa Hitchens, vice-president of the Center for Defense Information, said she believed China will not easily give up its manned space program because of disasters like the Columbia tragedy.

She told the Washington Profile magazine that China had planned to send a human into space for quite some time, and it was very close to realizing that dream.

Despite all the confidence expressed in China's manned space program, Zhang and his colleagues said they will move ahead as if "treading on thin ice," working through every step conscientiously and meticulously.

Zhang conceded that the Columbia tragedy had sounded alarm bells for China's aerospace industry.

He said it is important to learn from the incident and establish the cause of any problem that arose in the course of a space mission.

Equally important is to decide if changes are necessary to fix the problem and what kind of countermeasures should be taken, Zhang said.

Shenzhou craft chief designer Qi said accidents are most likely when a spacecraft is launched or re-enters the earth's atmosphere.

"The success of the (previous) launches does not mean that we have a thorough grasp of spacecraft technology," he was quoted as saying by China Space News Thursday.

"Although China's Shenzhou-series craft were not reused, unlike the US spaceships, the loss of Columbia space shuttle shows we always need to be cautious and meticulous in scientific undertakings."

Asked if an experiment designed by Beijing Jingshan School students for the ill-fated Columbia could be continued in China's manned space mission, Zhang said the spacecraft is mainly for sending astronauts into orbit. Scientists have so far not considered adding many experiments to the mission this year, he said.

Student Zhao Chen said he hoped the failed experiment, which aimed to measure the effect of weightlessness on silk production by silkworms, could be resurrected in Chinese spacecraft or satellites.

Zhang encouraged the students to continue their interest in space science, and promised to carry their experiments aboard Chinese spacecraft or satellites in the future.

(China Daily February 14, 2003)