Development of Graphene Oxide Induced Nanoscale Energetic Coordination Polymer Based Propellant for Microthruster

Description

The development of micro/nano satellites is very attractive because of the combination of low lifecycle cost and high functionality. A micropropulsion system is necessary for the micro/nano satellite to achieve station keeping, attitude control, gravitation compensation and orbit adjust. Among various micropropulsion systems, microthrusters with solid propellants have attracted more attention due to their reduced system complexity, no moving parts and very low propellant leakage possibility. However, the solid propellants currently used in microthrusters (e.g. ammonium perchlorate, sodium azide, lead styphnate) are facing the problems of environmental pollution, biological toxicity or high sensitivity. Replacing these traditional propellants with green alternatives (e.g. sodium nitrate) often leads to a decline in propulsion performance. Therefore, the requirement of developing new solid propellants for microthrusters is urgent. In this project, a non-toxic and pollution-free green solidpropellantwith high gas yield will be developed and integrated into amicrothruster. A nanoscaleenergetic coordination polymer (ECP)constructed from transition metal ions, nitrogen-rich bis-tetrazole ligands and graphene oxide (GO) will be prepared as a solid propellant. The composition design of the proposed new propellant is expected to bring many advantages, such as low sensitivity due to the rigid structure of ECP, high energy density and rich nitrogen and carbon sources originated from the tetrazole ring and GO’s energetic functional group, reduced size caused by the confinement effect among GO layers, excellent self-sustaining combustion ability promoted by the heat and mass transfer effects of GO, and high stack density due to the van der Waals forces among the GO layers. These characteristics will solve the problems of toxicity, harm and quenching of the current solid propellants used in microthrusters, and also make up for the serious heat loss in micro-devices. There are several critical engineering challenges and scientific issues that will be addressed in this project in order to realize clean and efficient propulsion: (1) design appropriate experiments to induce the energetic groups into the GO layers and form nanoscale ECP; (2) adjust the ratio among GO, metal ions and nitrogen-rich ligands to achieve highest heat release, complete combustion and maximum clean gas production; (3) design a MEMS-based microthruster considering the simplification of processing, convenient charging and gas acceleration; (4) fill the developed propellant into the microchamber with large density and good adhesion; (5) measure two key performance indicators of the microthruster: average thrust and specific impulse.