It does not qualify as Russian SF, but:
I just want to add, that Lem is better translated to Russian, than to English in my opinion. Possibly, word play is easier to translate due to similarity in Polish and Russian (I mean words like "электрыцарь" ).
Lem is probably my favourite SF author, and I highly recommend everybody to read him. My personal favourite novel is "Эдем". It is about spaceship crashing on a planet with highly organized life forms and the problems of contacting and understanding them.