Researchers at GW have developed a novel, cost-effective, energy-efficient solution to increase ignition system lifetime for micro-cathode arc thrusters. For example, a vacuum arc is an electrical discharge between two conducting materials which occur in vacuum. Vacuum arcs are utilized in various applications such as circuit breakers, ion implantation and thin film coatings. They can also be utilized in small satellite electric propulsion (more specifically cube satellites or CubeSats). CubeSats are also currently being utilized in a growing number of space missions. Further, the benefits of CubeSats can include: the potential for quick development and iterative design cycles for new technologies, a cheap alternative for testing non-flown space equipment, personalized missions which can achieve an unlimited variety of goals, and they have opened the doors to a whole new space industry.
Experiments have been conducted to study the breakdown mechanism in the micro-cathode arc thruster, with an aim to understanding the nature of discharge ignition and extending the ignition system lifetime. The results suggest that optimal materials of the insulator and electrode geometries are important factors. Two opposing processes, namely degradation of the conductive film from the interelectrode insulator and its re-deposition due to cathode spot erosion, have been observed. It has also been found that the initial resistances may vary from hundreds of ohms to thousands of ohms based on initial connectivity of the film and electrodes. After pulsing however, resistances have been found to stabilize in a typical pattern. Materials capable to withstand high temperatures are shown to be beneficial for extending the lifetime.
Fig. 1 – Aspects of the experiment
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