Room-temperature catalytically reactive ammonium dinitramide–H2O2 monopropellant for microsatellites

Abstract

Room-temperature catalytically reactive ammonium dinitramide (ADN)-based green monopropellants are interesting for space applications, particularly for microthruster applications. In this study, a blend of ADN and 90-wt% hydrogen peroxide monopropellant was developed and its catalytic reactivity was investigated at different temperatures. An optimal ADN–hydrogen peroxide monopropellant (AHMP) was fabricated at a weight ratio of 40:60 wt:wt (ADN:90-wt% H2O2). The theoretical vacuum specific impulse of AHMP was 206 s, 20% higher than the specific impulse (172 s) of 90-wt% hydrogen peroxide. The thermal properties of AHMP were evaluated using thermogravimetric analysis–differential scanning calorimetry, which revealed that thermal behavior of AHMP containing ADN and 90-wt% hydrogen peroxide was similar to their pure compound. The storability of AHMP was estimated using Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Notably, AHMP could be stored at low temperatures (2–3 °C) for 4 months and at room temperature (20–23 °C) for 1.4 months without chemical changes. Furthermore, drop test and microthruster test were performed to determine the reactivity of AHMP with a catalyst (Pt/La/Al2O3). The response time of the catalyst on the decomposition of AHMP was approximately 104.6, 24.8, and 7.0 ms at 23, 60, and 120 °C, respectively. This study on the AHMP green monopropellant paves the way for further studies on improved ADN–hydrogen-peroxide-based monopropellants for microthruster applications.