As he left prison, Danilov -- who was convicted in 2004 of passing classified information to China via satellite technology -- vowed to continue studying science, RIA Novosti reported.
"Of course, I will be involved in science, just not related to outer space," Danilov said at a press conference after his release, "because everything space-related in our country is a state secret."
Danilov was paroled this month with six years remaining on his 14-year prison sentence.
He has maintained that the information he was accused of giving out had been available in scientific journals and had been declassified for more than 10 years.
"No one has told me yet what secrets I am privy to," he said after his release.