Review of multimode space propulsion

Multimode propulsion is the integration of two or more propulsive modes with shared propellant into a single spacecraft propulsion system. Multimode propulsion is emerging as an enabling technology that promises enhanced capabilities for spacecraft and space missions, and can therefore play an important role in the future of in-space propulsion. Multimode propulsion has the potential to provide unprecedented flexibility and adaptability to spacecraft as a direct result of shared propellant, and can provide mass savings for certain missions. These benefits can apply regardless of spacecraft size. Additional mass savings may be realized by sharing thruster hardware between modes, especially for small satellites. Numerous multimode concepts have been explored and documented in the literature. Concepts combining cold gas, monopropellant, bipropellant, and solid chemical propulsion with electrothermal, electrostatic, and electromagnetic electric propulsion have all been investigated. Electrospray electric propulsion paired with monopropellant chemical propulsion has perhaps received the most recent attention. We review the nature of multimode propulsion, mission analyses, benefits, and specific multimode concepts.