Pirx, an experienced pilot, is hired to go on a top-secret mission to evaluate some 'nonlinears' (an experimental model of android) for use as crewmembers on future space flights. Pirx and this intriguing crew are sent out to launch two satellites into the rings of Saturn, but he is determined to find out and identify a hostile unhuman coworker among them.
Sergei Desnitsky
Vladimir Ivashov
Aleksandr Kaydanovskiy
Tõnu Saar
Zbigniew Lesień
Bolesław Abart
Ferdynand Matysik
Igor Przegrodzki
Faime Jurno
Zygmunt Bielawski
Janusz Bylczyński
Adam Cieślak
Edmund Fetting
Józef Fryźlewicz
Marek Idziński
Mieczysław Janowski
Z. Jurkowski
Jerzy Kaliszewski
Eugeniusz Kujawski
Ewa Lejczak
Erwin Nowiaszak
Henryk Talar