The U.S. Nuclear Command, Control, and Communications (NC3) enterprise’s APU Exhaust Box located on the E-6B platform fails to adequately dissipate hot APU exhaust gasses outside the aircraft fuselage when the APU operates for extended periods of time.  Structural damage to the aircraft has resulted in Enhanced Phase Maintenance Heavy (EPMH) at a cost of $1M+ per aircraft. To address this issue the Government is seeking a prototype solution which resolves exhaust leakage from the Exhaust Box System to avoid aircraft structural damage.