A Chinese-born physicist Monday pleaded guilty before a US court to illegally exporting American military space know-how to China, US officials said.

Naturalized US citizen Shu Quan-Sheng, admitted handing over to Beijing information on the design and development of a fueling system for space launch vehicles between 2003 and 2007, the Justice Department said.

Shu, 68, pleaded guilty to violating the Arms Export Control Act by helping Chinese officials based at the space facility on southern Hainan island to develop manned space flight and future missions to the Moon.

He also acknowledged he had sent them in December 2003 a specific military document detailing the design of liquid hydrogen tanks crucial to launching vehicles into space, the Justice Department said in a statement.

Shu, who is the head of a high-tech company AMAC International based in Newport News, Virginia with offices in Beijing, admitted a third charge of bribing Chinese officials to the tune of some 189,300 dollars.

The bribes helped him to secure for an unidentified French company a four-million dollar contract for the development of a liquid hydrogen tank system, awarded to the French firm in January 2007.

China sent its first man into space in 2003 and followed that with a two-man mission in 2005.

The Shenzhou VII, China's third manned foray into space, blasted off from Jiuquan Satellite Launch Centre in northwest China in late September.

One of the three astronauts on board, Zhai Zhigang, became the first Chinese astronaut to successfully complete a space walk, and the crew was feted with a hero's welcome on its return to Earth.

Premier Wen Jiabao told the Chinese mission control's dozens of technicians the mission was "a victory for China's space and technological" programs.

"Your historical feat will be remembered by the country and the people," he said.

China is now planning to launch two more unmanned craft by 2010, as well as another manned spaceship with a crew of three to start work on a Chinese lab or space station.

Sentencing in Shu's case has been set for April 6, 2009. He faces a maximum of 10 years in prison and a million-dollar fine for each of the two violations of the Arms Control Act. He could also be sentenced to five years in prison for bribery.