What is the optimal fuel for space flight? Efficiency, cost, and environmental impact

The space flight industry is growing rapidly. In order to increase its efficiency and ensure sustainability as the industry continues to expand, the present study investigated and compared a set of rocket propellants to determine the most and least advantageous fuels to use going forward. Chemical properties, production and storage cost, and environmental impact were the factors considered. We hypothesized that the propellants currently used the most in terms of launch frequency, i.e., RP-1 (kerosene) and hydrazine, would perform best in our comparison. To compare various properties, we derived three novel equations, providing numerical, objectively comparable values for each considered fuel in terms of its economic, environmental, and efficiency potential, equally weighed. Results showed ammonium dinitramide (ADN)-based propellants, Al/Ice, and liquid methane are the most optimal fuels, with hydrazine, liquid hydrogen, and nuclear thermal propulsion (NTP) being the least optimal out of the nine fuels compared. In conclusion, we challenged the hypothesis and formed a recommendation on further research and potential implementation of novel and less-used fuels mentioned above, which should be pursued as a priority, to ensure a sustainable future for the space industry and the planet as a whole.