Design and Testing of a 100-mN Class Water Micropropulsion System Using Wire-Fed Magnesium Combustion

In this study, the brand-new micropropulsion system is introduced to cover the thrust performances shorthanded by the exiting systems. It uses water as an oxidizer and a magnesium wire as a fuel. We constructed the lab-scale model of this micropropulsion system, and conducted several experiments to obtain the reaction rate of magnesium wire in water-vapor flow. Reaction rate showed almost proportional dependence on water-vapor mass flow rate. We constructed the revised version of lab-scale model, and will continue experiments for detailed analysis of combustion

Miniature Water Ion Thruster; 1 km/s-class Delta-V for a 6U CubeSat

A propulsion system gives CubeSats the capacity to change their orbit on their own, and in terms of achieving a large delta-V, electric propulsion has an advantage. Installing the electric propulsion on CubeSats has difficulties such as a high-pressure gas system, electrical components, and the drop of the efficiency because of the miniaturization. To clear these problems, the water ion thruster is proposed as a candidate for the CubeSats’ electric propulsion. Water has an absolute advantage of applying for CubeSats’ propulsion system in the point of safety. In addition, water is a liquid phase at room temperature and atmospheric pressure, and it makes easy to store and handle it. The thrust measurement and the improvement of the thruster based on experiments were conducted. The thrust and the specific impulse were estimated as 226 ± 19 μN and 384 ± 33 s at the highest performance point with 36.5 W power consumption of all system. It achieved a delta-V of 504 ± 43 m/s with the 1 kg of propellant for an 8 kg and 6U CubeSat

Development of the Water Resistojet Propulsion System for Deep Space Exploration by the CubeSat: EQUULEUS

In this study, Water micro-propulsion system AQUARIUS (AQUA ResIstojet propUlsion System) is proposed for 6U CubeSat: EQUULEUS to explore the deep space. AQUARIUS uses storable, safe and non-toxic propellant: water, which allows for downsizing of whole propulsion system to 2U and storing 1.2 kg water. Liquid propellant storage allows design of all propulsion systems below 100 kPa. The waste heat of communication components is reused to cover high latent heat of water. AQUARIUS has 4.0 mN and specific impulse of 70 s by less than 20 W power consumption. Breadboard model was designed and tested successfully. Engineering model is under developments and operations by using whole systems of EQUULEUS. AQUARIUS will be equipped with EQUULEUS scheduled to be launched in 2019 by SLS (Space Launch System)

Influence of Discharge Oscillation on Hall Thruster Performance *

Influence of discharge oscillations at frequency range of 10-100kHz was investigated using the 1kW class sheath type Hall thruster. Lifetime, that is, wall erosion was examined by means of spectroscopy. The erosion rate in unstable operation was twice as large as that in stable operation. Plume divergence was also measured. The full angle at half maximum of thruster plume was increased from 14.4 to 18.2 degree when the operation was changed from stable operation to unstable operation. However, the oscillation amplitude had little relation with the erosion rate, the plume divergence and the thruster performance. These results would indicate that the ionization zone configuration would affect lifetime, the plume divergence, thruster performance and oscillation rather than oscillation in itself would affect lifetime, the plume divergence and thruster performance

Oscillation Reduction of an Anode-Layer-Type Hall Thruster by Azimuthal Propellant onuniformity

Discharge current oscillation in the frequency range of 10-100 kHz causes serious problems in using anode layer type Hall thrusters in space. As a novel approach to stabilize the discharge, azimuthally nonuniform propellant flow was created in an acceleration channel. A plenum chamber and hollow anodes were azimuthally divided into two or four sections and xenon flow rates supplied to them were controlled. As a result, the oscillation amplitude significantly decreased and oscillation-free operation was achieved at all magnetic flux densities

Mode transition of plasma expansion for laser induced breakdown in Air

High-speed shadowgraph visualization experiments conducted using a 10 J pulse transversely excited atmospheric (TEA) CO2 laser in ambient air provided a state transition from overdriven to Chapman–Jouguet in the laser-supported detonation regime. At the state transition, the propagation velocity of the laser-supported detonation wave and the threshold laser intensity were 10 km/s and 1011 W/m2, respectively. State transition information, such as the photoionization caused by plasma UV radiation, of the avalanche ionization ahead of the ionization wave front can be elucidated from examination of the source seed electrons