Critical Review of the Scientific and Economic Efficacy of Lithium Lorentz Force Accelerators

Abstract: Electromagnetic propulsion technology has been thought to provide a potential form of future spacecraft propulsion for some time. In contrast to ion thrusters, which utilize the Coulomb force to accelerate positively charged species, electromagnetic propulsion systems utilize the Lorentz force to accelerate all species in a quasi-neutral state, providing significant technological benefits over ion thrusters. Several forms of electromagnetic propulsion have been researched and developed, such as the Variable Specific Impulse Magnetoplasma Rocket, pulsed inductive thrusters, and the electrodeless plasma thruster. One of the most promising forms of electromagnetic propulsion, however, has been the magnetoplasmadynamic thruster. Whereas other electromagnetic propulsion systems provide high specific impulse values but low thrust capabilities, magnetoplasmadynamic thrusters have demonstrated the potential for both high specific impulse values and high thrust densities. However, these thrusters are not without drawbacks and suffer from issues such as electrode erosion. A proposed subtype of these thrusters, known as the Lithium Lorentz Force Accelerator, has been shown to address some of these issues. As is demonstrated in this paper, mission duration is not notably improved by the use of Lithium Lorentz Force Accelerators except for mission distances beyond the capabilities of current propulsion technology. It is also shown that increasing the amount of batteries onboard a spacecraft does not necessarily decrease mission duration due to the specific power of current battery technology, which is on the order of 10^3 W/kg, but that new developments in nuclear energy technology may allow these thrusters to become efficacious for missions for which current propulsion technology is insufficient.