A US military contractor is alleged to have tried to sell Uncle Sam's satellite secrets to someone he thought was a Russian intelligence officer, the Feds claim.

Gregory Allen Justice, 49, of Culver City, California, worked as a security tester on military satellites, including the GPS system, the Milstar military communications network, and various spying hardware in orbit.

He was arrested by the FBI on Thursday after allegedly selling hardware designs to an undercover agent. The Feds claim that since February this year, Justice met the g-man five times, and allege that four of those times he was paid $500 or $1,000 for copies of satellite schematics, blueprints and test files.

Justice did not have access to classified material, but, claimed Special Agent Peter Lee in an affidavit, he allegedly handed over proprietary trade secrets that, under international arms laws, could not be moved from the US without an export licence – in breach of arms laws, as well as trade secret protections.

"Mr Justice allegedly placed his own interests of greed over our national security by providing information on sensitive US technologies to a person whom he believed was a foreign agent," said Assistant Attorney General John Carlin on Friday.

"In the wrong hands, this information could be used to harm the United States and its allies. The National Security Division will continue to relentlessly identify, pursue and prosecute offenders that threaten our national security."

Special Agent Lee also alleged that in 2015, Justice sent a technical schematic to the Russian consulate in California. After computer records showed that he had been copying work files onto a USB drive, he was placed under surveillance.

Justice had money problems, Special Agent Lee claimed, adding that the man's wife was "housebound" and seriously ill. However, Justice also appears to have been caught in a catfishing scam and had sent large sums of money to a woman known only as "CM".

Special Agent Lee added that CM was a woman living with her boyfriend and child in California, but had sent Justice pictures of herself that were later found to be of an Eastern European model. Justice sent the woman thousands of dollars – and expensive gifts – in the belief he was supporting her, claimed the FBI agent.

"The enforcement of US laws that prohibit the acquisition of specified economic information and defense-related items is vital to national security and can prove to be a challenging mission when set against the backdrop of legitimate international trade, vast amounts of which occur every day in the United States," said Assistant Director in Charge Deirdre Fike.

Justice exchanged a series of USB drives containing classified data with the undercover operative in exchange for thousands of dollars in cash – for which he signed a receipt, alleges the agent.

The engineer was arrested this summer and has been charged with economic espionage and violating the Arms Export Control Act. If convicted, he faces a possible 35 years in prison.

"Our nation's security depends on the honesty and integrity of those entrusted with our technological secrets," said US Attorney Eileen Decker.

"In this case, the defendant sought to undermine our national security by attempting to sell proprietary and controlled information about satellites to a foreign government's intelligence service. Fortunately, law enforcement agents were able to timely and effectively intervene to protect this critical technology." ®