The Center of Applied Space Technology and Microgravity ZARM disposes of an experimental setup designed for the study of flow processes and heating mechanisms in arcjet propulsion systems. The third iteration of the setup, known as Ionized Noble Gas Accelerator “INGA III”, consists mainly of a vacuum chamber, pressure sensors, a mass flow controller, power supplies for the controlled generation and maintenance of an electric arc and a small scale, modular arcjet propulsion system. The arcjet thruster itself consists mainly of a tungsten cathode, a de laval nozzle whose walls act as an anode, an insulator made of sintered boron nitride and several sensors and propellant supply lines. In addition, the modular design of the thruster enables a quick changeover between different nozzle geometries. The arcjet thruster operates at propellant volumetric flows of up to 2 cm3/s and uses a high-voltage power supply of up to 2000 V for the ignition and a high-current power supply of up to 100 A for the stationary operation. The INGA III setup allows the comparison of different arcjet thruster configurations and propellants, the study of the relation between supplied electric power and thrust and the experimental validation of numerical models for arc jet propulsion systems.