This thesis reports the results of an experimental investigation of film cooling in a supersonic environment using a modified version of an apparatus originally developed by Daanish Maqbool. A test matrix of conditions relevant to those found in the nozzle extension of the NASA J-2X rocket engine was used as the basis for the testing plan. A film heater was designed and constructed to enable operation at all points in the test matrix. Temperature-time histories from thermocouples embedded in the test section walls were used to compute the spatial evolution of the film cooling effectiveness at each test condition. The results were compared to numerical simulations by NASA's Loci-CHEM CFD tool. Standard speed (30 Hz) Schlieren videos of the film injection region were recorded and new machine vision-based techniques for automatically extracting flow information from Schlieren images were implemented.