Koosbane was a planet near Klingon Empire space, relatively proximate to the planet taD. As of the 24th century, it was a largely frozen world, consisting of an ice surface over a saline sea. Approximately seven million years BCE, the natives of Koosbane died out. An archaeological study conducted in the year 2365 first discovered evidence of this ancient civilization.
Ambassador Worf suggested the al'Hmatti of taD could be relocated to Koosbane if a peaceful settlement could not be reached between them and Klingon Empire. This proposal was rejected by both the al'Hmatti and the Federation Council. (TNG novel: Diplomatic Implausibility)