Review of chemical-electric multimode space propulsion

Multimode propulsion is the integration of two or more propulsive modes into a single spacecraft propulsion system. In a multimode propulsion system, the key attribute is shared propellant between the different propulsive modes. 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. Specifically, multimode propulsion has potential to provide unprecedented flexibility and adaptability to spacecraft, as well as provide mass savings for certain missions. These benefits extend to both medium and large spacecraft, as well as 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 concept of multimode propulsion, mission analyses, benefits, and specific multimode concepts.