Kris
Kris reacts to situations logically, and stays in control of himself and others. He is at the core of all events, and madness driven by other characters evolves around him. His logical decisions show when he sees the ghost-like figure of a girl. He first follows it secretly to find its identity, then inquires the scientists about it. Despite their secretive attitude, he does not let emotions such as frustration and anger interfere. When he first sees Hari, he also does not make signs of shock, or fear legible to her. While her appearance creates a sense of madness, he acts as if everything is normal, while reaching for a gun in case Hari proves to be dangerous. His logical nature also becomes evident when he is able to remain completely sane when Hari freezes to death. Learning from past experience that she will regain life in a moment, he seems contemplative about it, rather than feeling strong emotions.
Dr. Snaut and Dr. Sartorius
The two scientists maintain a secretive attitude throughout the film. They do not show signs of welcoming, while only informing Kris of vague facts about the space station and their research at a superficial level. They purposely hide about their experiments on Solaris Ocean and Dr. Gibarian to Kris in the beginning. They inform Hari about her identity while Hari’s emotional state is extremely unstable, without informing Kris, which heightens the madness. However the scientists also seem to suffer because of materialization by Solaris Ocean, and they are not completely aware of the results of their research.
Hari
Hari is a materialization of Kris’s ex-wife, who committed suicide. Unlike Kris, she has a tendency to respond to new knowledge very emotionally, and often sinks into a state of panic. She experiences identity crisis as he learns that she is not a human being. It gets more serious as she discovers her past from Kris, and she attempts to commit suicide. She expresses the result of madness imposed by the scientists.