Solaris

Solyaris is a movie starring Natalya Bondarchuk, Donatas Banionis, and Jüri Järvet. A psychologist is sent to a station orbiting a distant planet in order to discover what has caused the crew to go insane.
A psychologist is sent to a space station orbiting a planet called Solaris to investigate the death of a doctor and the mental problems of cosmonauts on the station. He soon discovers that the water on the planet is a type of brain which brings out repressed memories and obsessions.