Abstract: A foil segment bearing comprises a bearing backing with a through opening. A shaft is arranged in the through opening such that a gap exists between the shaft and the bearing backing. The foil segment bearing also has at least one first bearing segment and one second bearing segment with respective inner surfaces. Each of the respective inner surfaces defines a bearing surface with an adjustable circumference. The bearing segments are arranged in the bearing backing at a distance from the shaft such that a gap exists between the shaft and the bearing segments. The foil segment bearing also has a foil arrangement arranged in the gap between the inner surfaces of the bearing segments and the shaft. The foil segment bearing also has an adjustment mechanism configured to set a geometry of the gap.