Dongfan 'Greg' Chung, 73 and a resident of Orange County, California, was found guilty of economic espionage and acquiring information on demand using his "secret" classified clearance.

The former employee of Rockwell International's space and defense unit, which was taken over by Boeing in 1996, was convicted of multiple counts related to his decades-long espionage.

After a three week trial, Judge Cormac Carney "found Chung guilty of conspiracy to commit economic espionage, six counts of economic espionage to benefit a foreign country, one count of acting as an agent of the People's Republic of China and one count of making false statements to the FBI," the Justice Department said.

Prosecutors said Chung stole and passed along Boeing trade secrets related to the space shuttle and the Delta IV rocket programs.

Chung, who was arrested in February 2008, was to remain in custody pending sentencing November 9.

Salvador Hernandez, Assistant Director In Charge of the Federal Bureau of Investigation in Los Angeles, said that "the cost of Mr Chung's traitorous actions to American security and the economy cannot be quantified, but have now been exposed, and his ability to exploit critical technology has come to an end.

"FBI counter intelligence agents and NASA received the full cooperation of the Boeing Company in building this three-year investigation, the successful outcome of which marks the first conviction by trial under the Economic Espionage Act of 1996," Hernandez added.

"I'm confident this milestone conviction will serve as a deterrent to would-be spies contemplating theft of precious US secrets."

Chung's espionage apparently began in the 1970s, with prosecutors alleging that individuals in China's aviation industry began "tasking" the former engineer with collecting specific information from 1979 onwards.

His years of service as a Chinese spy, which included multiple trips to China for meetings with senior People's Liberation Army officials, began to unravel when investigators unmasked another Chinese agent.

The case last year against engineer Chi Mak, led agents from the Federal Bureau of Investigation and NASA counterintelligence to Chung.

In late 2006, agents from both agencies raided Chung's house and found more than 250,000 pages of documents containing information that included "decades' worth of stress analysis reports, test results and design information" for the US space shuttle, the Justice Department said.

Chung's conviction, for which he could be sentenced to 15 years on each charge of economic espionage, comes as the United States winds down its space shuttle program and prepares to send astronauts back to the moon.

US plans to return to the moon, with the goal of establishing a lunar base for manned trips to Mars, have sparked renewed space competition reminiscent of that which preceded the first moon landing, 40 years ago this Thursday.

China has said it aims to put an unmanned rover on the lunar surface by 2012, and a man on the moon by 2020 -- when the United States expects to send men back to the moon on the successor space vehicle to the shuttle.

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