LOS ANGELES—A former engineer at a Southern California company was sentenced on Nov. 17 to nearly four years behind bars for stealing technology developed for use by the U.S. government to detect nuclear missile launches, track ballistic and hypersonic missiles, and to allow American fighter planes to detect and evade heat-seeking missiles.

Chenguang Gong, 59, of San Jose, was sentenced to 46 months in federal prison by U.S. District Judge John F. Walter, who also ordered him to pay $77,408 in restitution and fined him $100,000, according to the U.S. Attorney’s Office.

Gong pleaded guilty in July in Los Angeles federal court to one count of theft of trade secrets.

Gong—a dual citizen of the United States and China—transferred more than 3,600 files from a Los Angeles-area research and development company where he worked to personal storage devices during his brief tenure with the company last year, according to his plea agreement.

The company was not named in court papers.

The files Gong transferred included “blueprints for sophisticated infrared sensors designed for use in space-based systems to detect nuclear missile launches and track ballistic and hypersonic missiles, as well as blueprints for sensors designed to enable U.S. military aircraft to detect incoming heat-seeking missiles and take countermeasures, including by jamming the missiles’ infrared tracking ability,” prosecutors said.

Some of the files were later found on storage devices seized from Gong’s temporary residence in Thousand Oaks, federal prosecutors said.

According to his plea agreement, the intended economic loss from Gong’s theft exceeds $3.5 million.

Gong was hired by the company in January 2023 as an integrated circuit design manager responsible for the design, development and verification of its infrared sensors, federal prosecutors said.

Gong transferred thousands of files from his work laptop to three personal storage devices, including more than 1,800 files after he had accepted a job at one of the company’s main competitors, according to his plea agreement.

According to the U.S. Attorney’s Office, many of the files “contained proprietary and trade secret information related to the development and design of a readout integrated circuit that allows space-based systems to detect missile launches and track ballistic and hypersonic missiles and a readout integrated circuit that allows aircraft to track incoming threats in low visibility environments.”

The information was among the company’s most important trade secrets that are worth hundreds of millions of dollars, authorities said.

Prosecutors also said that between 2014 and 2022, while working for several U.S. tech companies, Gong submitted applications to “Talent Programs” administered by China designed to identify people with skills and knowledge in advanced sciences and technologies that would benefit the nation’s economy, including its military capabilities, according to court documents.