High-current Hollow Cathode Development

Completed TRL 4 (started at 3, targeting 4)

Description

We propose a detailed investigation of the thermal behavior and plasma plume properties as a function of the design parameters of the cathode. Specifically, we will build a prototype cathode with variable orifice diameters and keeper gap, and study the effect that these design parameters have on the plasma plume of the cathode as well as its thermal behavior. The temperature of the insert in a barium oxide hollow cathode is strongly related to its lifetime, with higher temperatures leading to shorter lifetimes due to barium evaporation. The cathode design must thus be optimized to allow the insert to operate at the proper temperature while still producing a stable, quiescent plasma plume.

Early work at GRC, JPL, and in academia have demonstrated the basic viability of hollow cathodes at these current levels, but systematic design optimization has not yet been performed in detail. These efforts will help to produce a 200-A cathode which is built upon the 30 years of GRC cathode heritage and capable of the long lifetimes required by missions to Mars and elsewhere.

Benefits

High-power (100-kW class) electric propulsion systems require high-current (200-A class) hollow cathodes, and although early work has been promising, significant questions remain as to the design, thermal performance, plasma operation, and lifetime of these devices. We propose to perform design optimization of a 200-A barium oxide hollow cathode, with the goal of demonstrating the stable thermal and plasma operation of a cathode design at temperatures compatible with required mission lifetimes in excess of 15 khrs.

Details

Technology area	Propulsion Systems > Electric Space Propulsion
Program	Center Innovation Fund: GRC CIF (GRC CIF)
Lead organization	Glenn Research Center, Cleveland, OH
Start date	2020-10-01
End date	2021-09-30

Project contacts

Listed on TechPort itself — the most direct way to ask about this specific project.

Timothy G Gray — timothy.g.gray@nasa.gov

How to get involved

This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

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