The purpose of this research was to determine detonation characteristics for propulsion applications when using liquid fuels at different droplet sizes and vapor fractions. We first used a detonation tube where we had fuel injectors to input liquid fuel to determine the characteristics of detonation. For measuring detonation cells, we used two techniques. The first technique was using soot foils; this allowed us to determine how liquid fuels at different droplet sizes affect the detonation speed and its behavior. We found that droplet sizes are an important factor that changes characteristics of detonations. When droplet size is bigger, the speed of the detonation is slow compared to when the droplet size is smaller. This happens because smaller droplet sizes evaporate faster than bigger droplets, which allows the detonation propagation speed to go faster. The second technique used was schlieren, which makes invisible flow elements, such as gases, air, and other transparent media visible. In this case, fluid density changes were made visible by bending light rays. These methods confirmed detonation propagation speed increases or decreases as we change the equivalence ratio of liquid fuel. Thus, this research demonstrates how certain detonation characteristics in propulsion applications could improve engine performance on spacecrafts.