It's available at youtube in 16 short segments. Russian only. No English subtitles. Part 1:
part 2, part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10, part 11, part 12, part 13, part 14, part 15, part 16
I looked at part of this just for fun, but I'm unable to make any sense of it without subtitles. There's lots of talking.
1000 Misspent Hours says it's a
philosophically inclined film, with the cosmonauts frequently taking time out from their explorations to consider and discuss the implications of what they’ve seen on Venus.
It was re-edited to make 2 other films: Voyage to the Prehistoric Planet and Voyage to the Planet of Prehistoric Women.
2/26/2010: Classic Sci-Fi Movies says,
The action is a bit thin and at times talky, so modern viewers accustomed to laser battles and frequent explosions, will find PB hokey However, the english-subtitled version of PB is well worth watching for fans of 50s sci-fi.