Abstract: This paper presents the results of an experimental study of the unsteady nature of a hypersonic separated turbulent flow. The nominal test conditions were a freestream Mach number of 7.8 and a unit Reynolds number of 3.5×107/m. The separated flow was generated using finite span forward facing steps. An array of flush mounted high spatial resolution and fast response platinum film resistance thermometers was used to make multi-channel measurements of the fluctuating surface heat transfer within the separated...