Quantum sources and single photon detectors have improved, allowing quantum algorithms for communication, encryption, computing, and sensing to transition from theory and small-scale laboratory experiments to field experiments. One such quantum algorithm, Quantum Key Distribution, uses optical pulses to generate shared random bit strings between two locations. These shared bit strings can be turned into encryption keys to be used as a one-time-pad or integrated with symmetric encryption techniques such as the Advanced Encryption Standard. This method of key generation and encryption is resistant to future advances in quantum computing which significantly degrade the effectiveness of current asymmetric key sharing techniques. This research first reviews previous and current efforts in free-space Quantum Key Distribution. Next, a derivation of the propagation and atmospheric simulation techniques used to model the propagation of an optical pulse from a LEO satellite to ground through turbulence is provided. An Adaptive Optics system, including both lower order tracking as well as higher order corrections using a Self-Referencing Interferometer, is modeled to correct for the aberrations caused by the atmosphere. The propagation, atmospheric, and adaptive optics models are then organized into a general optical propagation toolkit. Satellite positions are calculated using the Simplified General Perturbations model and are used with the optical propagation models to show the effects of using an adaptive optics system during a realistic satellite pass. Finally, the results from the models are compared to experimental data taken from a recent Japanese satellite experiment
