A new China-made software program that calculates radiation in outer space has prevented Chinese astronauts from getting radiation sickness during the country's two manned space missions, said a Chinese space environment expert on Monday.

"The space environment prediction technology will play a more important role during China's longer space flights and space walks," said Liu Siqing, a researcher with the Center for Space Science and Applied Research under the Chinese Academy of Sciences.

At the 36th Committee on Space Research (COSPAR) Scientific Assembly, which opened in Beijing on Monday, Liu said as China's future space program increases the time spent in outer space experts will face more challenges in protecting the safety of astronauts.

Liu led a group of researchers who were in charge of the space environment prediction for the flights of Shenzhou spaceships overthe past several years.

Based on radiation studies both at home and abroad, Chinese scientists developed the software to evaluate the radiation received by Chinese astronauts during their space flights, Liu said.

"During the missions of Shenzhou V and Shenzhou VI, researchers used the software to conduct real time calculations and monitor the exposure to radiation of the astronauts," Liu said.

"If the radiation exceeds safe levels, the directing personnel on earth will direct the astronauts to take measures to avoid the radiation and protect themselves," said Liu.

High-energy radiation is a major threats to the safety of the astronauts in space. The radiation may cause harm to the cells, tissues and organs of the astronauts, Liu explained.

(Xinhua News Agency July 18, 2006)