Ambient Atmosphere Ion Thruster (AAIT) Proof-of-Concept Modeling

Abstract

Demand for low-Earth orbit (LEO) satellites increases each year in all sectors, including government, commercial, and academia. The amount of available propellant limits satellite lifetime due to the necessity of drag makeup. The Ambient Atmosphere Ion Thruster (AAIT) is an electric propulsion device that uses in-situ ions as propellant, and is considered as an alternative method for satellite drag makeup. An important tool created from this analysis is a 0-D thruster mathematical model that integrates with the NASA International Reference Ionosphere (IRI) to provide ion and neutral species densities for an electrostatic electric propulsion (EP) approach. In this analysis Satellite Toolkit (STK) provides orbit propagation. This mathematical model predicts thrust, drag, and thruster power. Thrust-todrag ratio (T/D) and thruster power are averaged over the entire mission duration of one year and compared with various circular orbits and satellite configurations: 300-1000 km orbit altitude, 0-60° orbit inclination, low to high solar activity, 0.1-5.0 m satellite frontal area, 1-10 kV AAIT acceleration potential, and 1-10 m total AAIT grid area. Average T/D ratio greater than one is achievable for many AAIT and orbit configurations considered in this analysis; however, in this analysis most satellite missions at altitudes of less than 400 km may fall into the region where the T/D ratio is less than one. T/D ratio values of less than one may still benefit satellites by extending mission lifetimes for months or years with average power requirements less than 100 W.