LAUNCH VEHICLES HAVE MANY COMPARTMENTS WHICH ARE VENTED TO THE LOCAL EXTERNAL ENVIRONMENT.

LAUNCH VEHICLES HAVE MANY COMPARTMENTS WHICH ARE VENTED TO THE LOCAL EXTERNAL ENVIRONMENT. LOCAL HIGH PRESSURE AREAS CAN CAUSE HIGH ENTHALPY FLOWS INTO COMPARTMENTS AT ONE LOCATION WHICH ARE VENTED AT OTHER LOCATIONS DURING ASCENT. DURING REENTRY, HIGH ENTHALPY GASES ARE ENTRAINED AND EXPELLED FROM VENTED COMPARTMENTS DURING THE TUMBLING MOTION OF THE VEHICLE. THE INTERNAL COMPONENTS MUST BE PROTECTED FROM THE HIGH ENTHALPY GAS. FOR EXAMPLE, POOR PROTECTION COULD PRODUCE PARACHUTE OVERHEATING, YIELDING VEHICLE LOSS OR DAMAGE ON IMPACT. CURRENT TECHNIQUES USE ADIABATIC VENTING CODES AND A DECOUPLED HEATING ANALYSIS. THE HIGH AREA AND LARGE MASS OF SURROUNDING STRUCTURE INVALIDATES THIS APPROACH AND PRODUCES OVER CONSERVATIVE HEATING PREDICTIONS. THIS RESULTS IN UNNECESSARY AND COSTLY INTERNAL THERMAL PROTECTION MATERIALS TO BE APPLIED AND TPS CLOSEOUT REQUIREMENTS. THE COMPUTER TOOL NEEDED TO APPROPRIATELY ADDRESS THESE QUESTIONS DOES NOT EXIST AND SHOULD CONSIST OF A NONADIABATIC VENTING CODE COUPLED WITH A SET OF FREE AND FORCED CONVECTION INTERNAL HEATING OPTIONS AND TRANSIENT CONDUCTION ROUTINES.