Data on solar radiation on earth is readily available, however the solar radiation on Mars requires analytical expressions to predict. This model shows how custom components can be used to model the solar radiation on a horizontal and tilted surface based on measured optical depth of the Martian atmosphere from NASA’s Viking Mission, the aerocentric longitude, latitude, surface tilt and orientation. The results show the diurnal variation of the net irradiation on a horizontal surface as well as on a tilted surface. It also shows the net irradiation broken down into the direct, diffuse and reflected irradiation. This enables more accurate engineering studies and estimates of solar array size and performance.