A lot. I'm more interested in Espionage than the Space Program (I imagine if you asked nicely Roscosmos might give you footage), but to this day there is more material from the KGB from defectors than official sources (and this includes material going back a century). The biggest single dump of KGB archives was from Mitrokhin, who in the burst of freedom after the union dissolved walked off with a few hundred thousand papers he'd copied (The book version is a good read).
It will likely remain that way for many years, the Russian Federation is still chekist just as the Soviet Union was before it - those who criticize Putin do not live long.