Microwave

Macroeconomics

Ion source

Quantum mechanics

Beam (structure)

Engineering

Propulsion

Aerospace engineering

Materials science

Plasma volume

Ion thruster

Nuclear physics

Endocrinology

Atomic physics

Plasma

Telecommunications

Economics

Current (fluid)

Spacecraft propulsion

Thermodynamics

Physics

Nuclear engineering

Organic chemistry

Optics

Specific impulse

Volume expansion

Internal medicine

Electrically powered spacecraft propulsion

Medicine

Chemistry

Vacuum chamber

Thrust

Ion current

Volume (thermodynamics)

Production (economics)

Ion beam

Electrical engineering

Acta Astronautica

To improve the performance of the 10-cm-class microwave discharge ion thruster μ10 for use in future deep space exploration missions planned by the Japan Aerospace Exploration Agency (JAXA), a new discharge chamber was designed, and its performance was tested. The maximum beam current in the new discharge chamber geometry was 16% higher than that in the original geometry, which was used in the Hayabusa 2 space explorer, under the same discharge power. To investigate the reason for this performance improvement, the multi-charged ion ratio in the plume, the beam current density profiles, and the ion current in the discharge chamber were measured by probes. It was found that the multi-charged ion efficiency and the beam divergence efficiency in the redesigned configuration were not significantly different from those in the Hayabusa 2 configuration. This shows that the increase in the ion beam current enhances the thrust. In addition, it was confirmed that the total ion current inside the new discharge chamber is higher than that in the Hayabusa 2 configuration. The ion extraction efficiency, however, was lower than that in the Hayabusa 2 configuration. This suggests that the increase in the total ion current per unit of incident microwave power is the cause of the performance improvement. In the redesigned configuration, the thrust is 12.0 mN, the specific impulse is 3122 s, the discharge loss is 162 W/A, and the propulsion efficiency is 39.6% at the peak performance point.

Performance improvement of the μ10 microwave discharge ion thruster by expansion of the plasma production volume