A representative for St Petersburg’s court system said Alexander Kuranov, 76, would be sent to a high-security prison and fined 100,000 roubles ($1,000).
At the time of his arrest in 2021, Kuranov was the general director of St Petersburg-based Hypersonics Systems Research Facility, where he oversaw work on a new version of a Soviet-era hypersonic aircraft dubbed Ayaks.
President Vladimir Putin has repeatedly said that Russia is a world leader in hypersonic missiles – cutting-edge weapons capable of carrying payloads at up to 10 times the speed of sound to punch through air-defence systems.
Ukraine said in April that Russia had used five hypersonic Zircon missiles to attack Kyiv since the start of the year. Putin confirmed in February that Russia had used the missiles in battle.
Kuranov was accused of passing secret information to a foreign citizen about hypersonic technology research that he had worked on for a long time, the Interfax news agency reported in 2021.
The court spokesperson said his conviction came after two trials. Treason and espionage cases are traditionally held behind closed doors in Russia.
A number of Russian scientists in recent years have been charged with treason on suspicion of passing sensitive material to foreigners.
