<p>In solid propellant rocket motors, it is common to add solid particles of aluminum to the propellant in order to improve its burning behavior and consequently the vehicle performance. After burned, the particles transform into oxide that increases the plume outlet temperature and thermal radiation over the rocket backside that may affect the rocket’s integrity due to the high thermal load. In this work, the physical model of radiation heat transfer and a corresponding computational tool for application in solid rocket engine plumes were developed. The Discrete Ordinate Method (DOM) was employed to estimate the heat flux in a region around a rocket plume. The preliminary results were validated through comparison with experimental data extracted from literature. Results for local heat flux presented good agreement with data in the regions were the flow was accurately represented, confirming the validity of the methodology.</p>