China's lunar probe program has no purpose other than scientific achievement, and it is not competing with any other country, a senior official said yesterday.

Japan's adjustment of its lunar launch date will not influence China's launch plan, Hao Xifan, deputy director of the Lunar Exploration Center of the Commission of Science Technology and Industry for National Defense, said in an online interview yesterday.

"We will follow our own plan," he said.

On Wednesday, Japan said it would launch its lunar probe, Selena, on September 13 instead of today. It said some condensers were improperly installed, and this could affect one of its 14 projects.

In addition to China and Japan, India and Germany are also are trying to explore the Moon for the first time.

"China's Moon probe is independent and developed by ourselves. After more than three years' efforts, we have confidence in the project's success," Hao said.

"But there are many things we don't know in terms of technology. We have made preparations, but the technical risks are there," he said.

All technologies used in the lunar orbiter Chang'e I originates from China's Earth satellites. They need further testing in the lunar environment, he said.

Besides, the launching process also entails high risks.

The probe, Chang'e I, will be carried into deep space by a Long March 3-A rocket. The rocket has fired successfully in all 14 missions since 1994.

Jin Zhigang, deputy chief architect of the rocket, said any failure in the 50-odd movements of the launch could influence the fate of Chang'e I.

"The past 14 successes cannot guarantee the next launch will be successful and the carrier rocket is designed with a reliability index of 0.95, so strictly speaking, not every launch can be guaranteed a success," Jin said.

There have been 122 lunar probes, but only 59 or 48 percent were successful. The United States and the former Soviet Union both failed in their first lunar missions.

China has spent a total of 1.4 billion yuan (US$184 million) on the lunar orbiter project.

Sun Zezhou, deputy chief architect of the satellite system, said Chang'e I, weighing 2,350 kg, will circle the Moon for a year.

Its top missions include obtaining three-dimensional images of the Moon's surface, and measuring the thickness of its soil by using a microwave radiometer.

The orbiter will provide first-hand knowledge about the Moon and built a sound foundation for the next phases of the program.

The program is divided into three phases - "circling the Moon", "landing on the Moon" and "back to Earth".

Following the launch of the orbiter, China will launch a Moon rover in the second phase, another rover in the third phase, which will return to Earth with soil and stone samples from the Moon.

(China Daily August 17, 2007)