Dual-mode chemical/electrospray thruster for small satellites
MIME Thruster (Multimode Integrated Monopropellant Electrospray Thruster)
Dual-mode chemical/electrospray thruster for small satellites
Description
The Multimode Integrated Monopropellant Electrospray (MIME) Thruster is Froberg Aerospace's core propulsion product, offering a single thruster capable of operating in either a high-thrust chemical mode or a high-specific-impulse electric (electrospray) mode. The system uses a single propellant, a single feed system, and a single thruster body, with the operating mode selectable by design or on-orbit as mission needs evolve.
In chemical mode, the thruster delivers higher thrust (order of milli-newtons) at lower specific impulse for maneuvers requiring rapid delta-V, such as orbit-raising or collision avoidance. In electric (electrospray) mode, the same hardware delivers much higher specific impulse at micro-newton thrust levels for efficient, propellant-sparing station-keeping and fine orbital adjustments. Because both modes share the same propellant tank, lines, and valves, the combined system occupies a footprint typical of a single-mode thruster while enabling the full range of maneuvers achievable by chemical and electric propulsion separately.
This flexibility expands the achievable mission design space for small satellites, letting operators adapt to changing mission requirements post-launch and perform maneuvers ranging from large delta-V orbit transfers to rapid rendezvous. The technology has been matured through NASA SBIR Phase I and Phase II awards and was demonstrated operating in both chemical and electrospray modes using the same thruster and propellant in 2020. It has also been proposed as the basis for a multimode chemical-electric propulsion transfer stage for flexible cislunar operations under a further NASA SBIR award.