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
Bolesław Abart
Vladimir Ivashov
Aleksandr Kaydanovskiy
Zbigniew Lesień
Ferdynand Matysik
Igor Przegrodzki
Tõnu Saar
Zygmunt Bielawski
Janusz Bylczyński
Adam Cieślak
Edmund Fetting
Józef Fryźlewicz
Marek Idziński
Mieczysław Janowski
Jerzy Kaliszewski
Eugeniusz Kujawski
Ewa Lejczak
Erwin Nowiaszak
Henryk Talar