A Russian court has sentenced a physicist Valentin Danilov to 14 years in a Siberian prison for passing space secrets to China.

Danilov, 53, a professor at Krasnoyarsk Technical University in Siberia, was first arrested in 2001 on charges he attempted to sell technology to China based on his work on the effects of the space environment on man-made satellites.

He spent 19 months in prison before being cleared of charges in December 2003, but the verdict was overturned on appeal in December 2003. He was retried and found guilty of high treason earlier this month.

Russian authorities claimed his invention, a tool designed to examine ways to destroy redundant satellites, revealed state secrets. But Danilov has always maintained information he sold to China was already publicly available.

Danilov was sentenced and ordered to serve his sentence in a maximum security labor camp, the BBC reported Wednesday. His lawyer said she planned to appeal the sentence in the Russian Supreme Court, the Itar-Tass news agency said.