Aero-thermal tests for qualification of launch vehicle thermal protection systems are carried out with high power quartz tungsten IR lamps as the heat source. These lamps are assembled in front of reflectors for efficient incidence of heat energy on test article. Reflector shape is custom designed to improve transfer of IR radiation to the target specimen surface. To configure a high heat flux simulation capable heater modules with geometrical arrangement of reflectors, an algorithm was developed for modeling specular reflection using Monte-Carlo technique with Ray Tracing. The algorithm was validated with experimental measurements from a flat reflector heater module configuration. The ray tracing algorithm was then utilized for designing a reflector heater module capable of simulating an incident flux of > 160 W/cm².