A sublight starship drive that uses an interphased subspace field to propel the vehicle through normal space. Interphased drives are capable of propelling a starship to around .85C or more, depending on the augmentation in use, and because of the subspace fields that are used, it avoids standard Time dialation. However, because of the massive amounts of power required to propel a starship above .45C, Mrrshan starships rarely exceed this threshold.