Chung was found guilty of passing on secrets about the space shuttle
A Chinese-born engineer in the United States has been found guilty of passing space shuttle technology secrets to China, for more than 30 years.
Dongfan "Greg" Chung, 73, is the first person to be found guilty under a federal law, introduced in 1996, to counter economic espionage.
Mr Chung worked for Rockwell International, and then Boeing, until the FBI investigation began in 2006.
He will be sentenced in November, and could spend decades in prison.
A court statement said the judge in California had found Chung guilty of economic espionage, acting as a foreign agent and making false statements to the FBI.
The trial began on 2 June.
Chung, a naturalised American citizen, worked at Rockwell International from 1973. Rockwell's defence and space unit was taken over by Boeing in 1996.
Chung's defence team admitted that he took Boeing papers home, but said he had wanted the information so he could write a book.
All the information he had given to China, they said, was already in the public domain.
His lawyer Thomas H Bienert told the court: "Mr Chung walked an interesting line, and a risky line, but not a line that was criminal."
The defence team says it will appeal against the verdict.
Chung is to remain in custody until his sentencing on 9 November. He could face up to 90 years in jail.