Measurement technique enhancement program for high-enthalpy shock tunnel HIEST has been under going for the next five-year plan in JAXA. One of the focus of this program is accuracy evaluation of heat flux measurement under high-enthalpy stagnation condition above H_0=15MJ/kg (equivalent to flight Mach number 20 or higher). The heat flux measurement in HIEST will be compared with numerical simulation results and flight test results. Since there are many public ground testing data and flight data, Apollo configuration was selected as reference. Wind tunnel experiments has been performing in the impulsive facility HIEST. A configuration of this Apollo capsule model was AS-202 with maximum diameter of 250mm. To measure heat flux around the model, ninety-six miniature co-axial thermocouples were instrumented on the model. Angle-of-attack of the model will be varied from 0 degree to 30degree. Test will be performed with stagnation pressure of 20MPa to 60Mpa and with stagnation enthalpy from 3.5MJ/kg to 20MJ/kg. Real gas numerical simulation code with 3-D unstructured grid will be conducted. The distribution obtained at Re=1.0×10^6 shows fully laminar flow. While the distribution obtained at Re=2.6×10^6 shows natural transition at approximately Z=20mm.
