There is a ship. It is filled with multiple personality one of them is a blond woman and she is having sex with a mercenary guy name Mike, maybe. Everyone is a scientist or soldier on a long haul voyage through space possibly to colonize or to escape overpopulation. The Asian female character is depressed. The woman goes on a space walk in a sort of ATV and ends up running out of air due to a leak in her suit and is later found frozen solid and assumed to have committed suicide. I don't recall if she is thawed and revived. The book was paperback and very aged/old. I don't think it was The Expanse.