In this paper, a transformer coupled high gain DC-DC converter is proposed for applications in electrospray thruster systems. The proposed converter consists of a two-phase interleaved boost converter, a step-up transformer, and a Diode-Capacitor multiplier. The proposed converter enhances the reliability of the thruster by alternating the voltage across the extractor grids, which ensures the neutrality of the propellant. The paper addresses the grounding issue of the multi-mode thruster, which is pivotal to the successful operation of the propulsion system. A hardware prototype is presented and the theoretical and practical converter gains are analyzed and compared. The converter proposed in this paper is found to be highly modular and scalable in nature, enabling enhanced mission capabilities.