Ammonia fuelled space electric propulsion systems using C12A7:e- electride as electron emitter

Abstract

Given the significant changes taking place in the geopolitical global situation, and the derived supply chain issues for some traditional electric propulsion propellants like xenon, alternative propellants issue is perceived as a strategic topic to tackle, and ammonia (NH3) is becoming one serious candidate. Ammonia is increasingly being investigated to extend green hydrogen use by overcoming the storage and transportation issues of hydrogen. Ammonia characteristics like its superior energy density and low temperature and/or pressure needs for storage (10 bar at 20°C for liquid ammonia), make it very valuable for simplified unexpensive energy storage and transportation, and these characteristics makes it also especially suitable for on-board spacecrafts electric propulsion purposes. Based on our research activities on ammonia generation and dissociation processes with C12A7:e- electride as catalyst, this work will describe the most relevant characteristics and properties associated to the advantages of using the cheap and abundant ammonia, and will also present and discuss the results of the first successful tests performed with ammonia as fuel for a C12A7:e- electride based neutralizer, including relevant endurance tests in operation conditions. Additionally, the dual application as propellant and on-board energy generation system of ammonia will also be discussed.