The laser-assisted pulsed plasma thruster is considered a promising propulsion system to support the tasks of microsatellites because of its high specific impulse and low volume. Different from the traditional pulsed plasma thruster, laser-assisted pulsed plasma thruster uses the laser to replace the spark plug for ignition, which can avoid ignition failure and remove the side effect of carbon deposition. Both the thrust efficiency and impulse bit are expected to increase after the plasma flow produced by laser ablation is further ionized and accelerated. Since there are a few macro-performance prediction models in laser-assisted pulsed plasma thrusters, this paper develops a model based on the laser ablation model and electromagnetic acceleration model to capture macro-performances of laser-assisted pulsed plasma thrusters. In this model, the initial velocity and mass of plasma flow can be obtained from the ablation model, and the acceleration model is utilized to describe the electromagnetic acceleration process of plasma flow. With this combined model, the discharge current, voltage, impulse bit, specific impulse, and thrust efficiency can be estimated. The deviation between the predicted results and experimental results was less than 10%, verifying the correctness of the developed model. The effects of different parameters on the performance are further investigated with this model.

Atmosphere-breathing electric propulsion (ABEP) systems capture atmospheric particles for use as propellant. In the best-case scenario, such systems can undertake long-life space missions without carrying propellant from the ground. The present research mainly focuses on plasma discharge processes based on inductively coupled plasma generation from atmospheric particles in very low Earth orbit (120–250 km). The optical diagnosis is done when the N2 and O2 mixture is injected into the low-pressure discharge chamber. Numerous active groups can be identified from the emission spectra, including excited molecules, molecular ions, atoms, and excited atoms. The generation mechanism of active groups is also clarified to understand the ionization process. The variations of plasma parameters are analyzed for different ratios of N2 to O2, which can also be expanded to describe the potential behavior of ABEP systems in low Earth orbit. Note that this research is only a preliminary study and is not fully representative of the potential of ABEP systems. However, to develop ABEP systems, it is essential to understand the plasma behavior of discharge systems.