Deep Space Optical Communications (DSOC) Downlink Simulation with Varying PPM Order

Abstract During the course of a typical deep space mission like Mars Earth mission, there exist a wide range of operating points due to the different changes in geometry that consequently cause different Link Budgets in terms of received signal and noise power. These changes include: Distance Range, Sun-Earth-Planet Angle, Zenith Angle and Atmospheric conditions. The different operating points with different losses (background noise, pointing losses and atmospheric losses) lead to different capacities and data rates over the course of a typical Deep Space mission. Consequently, different engineering parameters are adjusted and optimized to combat some of these varying losses in order to get an acceptable data rate and bit error probabilities. This provides a good basis to undertake analysis and simulations of the various operating conditions that occur with the varying spatial orbital time periods on the resulting received signal power level, noise power level, capacity, data rates and bit error probabilities. This paper details results of simulations done in a typical Deep Space Optical Communication link operation.