Theoretical analysis of hydrides in solid and hybrid rocket propulsion

Chemical rocket propulsion can benefit by using hydrides that are able to store high volumes of hydrogen at ambient conditions that can be released during combustion. This paper offers a theoretical investigation concerning the use of hydrides as additives in hybrid fuels and solid propellants. Aluminum hydride is expected to generate interesting performance gains but lack of commercial availability makes industrial application unfeasible. As a consequence, attention is focused on other simple and complex hydrides used in other fields and readily available. A comparative analysis of theoretical performance of gravimetric and volumetric specific impulse, propellant average density, adiabatic flame features, and preliminary estimate of exhaust products is conducted. Eight different hydrides, potentially applicable as replacements for aluminum currently used in solid propellants and hybrid rocket systems are considered.