It is the future and the spaceship Ikarie XB-1 has set off from Planet Earth to scrutinise the distant world their instruments tell them should be able to support life, though they do not know what sort could be there. The journey will take fifteen Earth years, but only twenty-eight months in the parameters of how long they will actually spend in space, and the crew, the equivalent of a small town, are painfully aware everyone they know back home will be aged or even dead by the point of their return. However, they cannot allow this to get to them, as the voyage will throw up perils they were not aware of...
The Czech film industry was very productive in the Cold War years, and perhaps their most enduring contribution to the cinematic landscape was their predeliction for science fiction. Plenty of Eastern Bloc countries produced work in that genre, looking ahead to a supposedly brighter future, although many of them detailed issues which may arise, as if commenting on the state of their totalitarian authorities through the medium of the fantastique. In this case, drawn uncredited from a Stanislav Lem novel, it was less a dig at the Communist overlords that was on the menu than an acknowledgement that moving ahead under these conditions might actually be really scary.
Just as exploring space might be scary too, a theme which ran through many a sci-fi effort to come, with many finding links between this particular entry and those ahead, such as the television series Star Trek (the crew of seekers assembling to problem solve a threat every week) or 1979's classic movie Alien (discovering a menace to the crew which they had made the mistake of going out of their way to explore). Ikarie translates as Icarus, not the most optimistic name for your space mission, but quite apt as far as the plot went when burning up is a very real concern as they encounter a "black star" which infects certain characters with a special kind of space radiation.
That radiation sends the afflicted crazy, as if they have realised the unimaginable vastness of where they are travelling and their by comparison pitifully insignificant place in it; one of them is so horrified by this that he jeopardises the ship by sabotaging it, convinced he will never see Earth again and therefore entirely justified in destroying them all because carrying on with that knowledge is overwhelmingly terrifying so death is preferable. This is often described as a rather cold film, reflecting the characters' environment, yet its worries are very deeply felt, so it may be preoccupied with the technology to an extent - the special effects, including a Czech Robby the Robot, are quaint but nicely handled - but that does not take away from their sincerity.
Not that our home world is always welcoming: in a symbolic sequence the crew discover another ship drifting in the void and investigate. Inside are another crew, all dead and perfectly preserved with their gambling accoutrements scattered around, apparently decadent refugees from the twentieth century which spawned such horrors as Auschwitz and Oradour-sur-Glane as one of the explorers observes soberly, so the filmmakers were not out to champion their era as any kind of perfection. They were more interested in highlighting where it had all gone wrong, with downbeat, every silver lining (space travel!) has a cloud (deadly radiation!) thinking prevalent. Ikarie XB-1 was re-edited into an hour-long dubbed version in America which changed the finale of the original, a more cautiously hopeful conclusion though rather open-ended, to a silly punchline not unlike that of Mario Bava's more disquieting Planet of the Vampires, but the original was the one to see, a little dry perhaps but its unease was palpable and made for an intriguing work. Music by Zdenek Liska, and check out the dance moves.