The gamma-ray scattering technique has shown promise for the continuous measurement of atmospheric density from space vehicles. To understand and optimize the parameters of this technique, mathematical models have been derived and used to study design parameters such as gamma-ray source energy, source-to-detector separation, detector discriminator settings, and shield effectiveness. The predicted effects agree generally with the experimental results obtained in feasibility studies, and mathematical modeling promises to be an effective means for optimizing the design of the gamma-ray scattering technique for measuring atmospheric density.