The biopic Moscow-Cassiopeia and Teenagers In Universe was a movie phenomenon which basically ground Soviet Education System to a halt in 1973-74 since whole school districts all over USSR simply refused go to school and preferred many hours staying in massive lines just to get a desirable movie theater ticket to studying Physics and Math. So, in the best traditions of political expediency, school districts simply started buying wholesale tickets and deliver whole schools to movie theaters to a magic of a story of middle-school geniuses flying to a remote star to save a civilization which... well, a lot in common with modern West, danger of AI and loss of humanity. You can watch the Teens In Universe here (with English Subtitles):
The funny thing is that some people still remember that movies and even do DJ mixes:
But truth is, the biopic was so far and way ahead of anything what could be conceived then, that one is still forced to contemplate what could have been if the series would have been continued. But, of course, in 1974 The Big Space Adventure (In Russian), with Alexey Rybnikov's stroke of a musical genius soundtrack came out. Remarkably, in this video stills from both franchises are used.
I can say only one thing--it was intoxicating, dreamy, life-changing experiences and, yes, it was sexy in the best meaning of the term--leaving childhood and facing early adulthood and love.