System-Level CubeSat Propulsion Development for Next-Generation Deep-Space Missions

CubeSats have evolved from educational platforms into capable spacecraft for scientific, commercial, and exploration missions. Extending this capability to deep space and demanding Earth-orbit operations requires propulsion beyond current CubeSat state of practice. Deep-space transfers, precision manoeuvring, drag compensation, and long operational lifetimes demand high specific impulse, high total impulse, and efficient use of limited onboard power. This paper presents the system-level development of an advanced CubeSat Propulsion System (CPS) for deep-space-capable 12U missions. The CPS builds on miniaturised electric propulsion technologies developed by Mars Space Ltd, including the RIT-3.5 ion thruster and DN-3.4 dry neutraliser, to deliver a compact, scalable, flight-ready propulsion architecture that brings mission-class performance into a CubeSat form factor.

The MSL CPS integrates a high-efficiency ion thruster with neutralisation, a miniaturised flow-management system, propellant storage, a Power Processing Unit (PPU), and an auxiliary cold-gas subsystem for attitude control and fine manoeuvres. The design targets >75 kNs total impulse and approximately 3200 s specific impulse, with a 0.8–2.2 mN throttle range at