IoM | Segmentum

A Segmentum, also known as the Segmentae Majoris, is the largest sub-unit of Imperial space and there are five segmentae covering Imperial territory stretching across the entire Milky Way Galaxy. They are the central Segmentum Solar, the eastern Segmentum Ultima, the southern Segmentum Tempestus, the northern Segmentum Obscurus and the western Segmentum Pacificus. Each segmentum is divided into multiple sectors. The size of a sector varies according to local demands and stellar density. A typical sector might encompass 7 million cubic light years, equivalent to a cube with sides almost 200 light years long. Sectors are divided into sub-sectors, usually comprising between 2 to 8 star systems within a 10-light-year radius. This size is governed by the practical patrol ranges through the Warp of Imperial Navy starships. Because sub-sectors are divisions of worlds there are vast numbers of star systems within each sector which do not fall within a sub-sector.