Small Business Innovation Research/Small Business Tech Transfer
Integrated Energetic Ion Mitigation for High Power Plasma Cathodes
Project Description
The innovation proposed is a hollow cathode that integrates mitigation methods to suppress wear to the keeper. Recent advances in the magnetic topology in Hall thrusters has eliminated erosion of the thruster walls. As such the life limiting component of Hall thrusters has shifted to the cathode lifetime. Under a previous investigation aimed at understanding the impact of high energy ions in high current hollow cathodes, we mapped the energy spectra of cathode derived ions for both a barium oxide hollow cathode and a LaB6 hollow cathode. Energetic ions were clearly present and their intensity and peak energy tended to increase with increasing discharge current. Preliminary mitigations experiments showed promise in the use of an externally applied magnetic field as a way to reduce the peak energy of the emitted ion flux. The overall goal of this proposal is to produce a hollow cathode with integrated energetic ion mitigation technology. This cathode will be tested in magnetic field environments characteristic of Hall and gridded ion engines. It will provide a good body of experimental evidence of how to successfully mitigate cathode erosion for the high powered thrusters currently under development. Additionally, an energetic ion mitigation method could be directly integrated into the cathode design for the recently proposed Asteroid Retrieval Mission (ARM) which is currently baselined to use 4-5 10 kW class magnetically shielded Hall thrusters.
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Anticipated Benefits
The direct application of long life, high current hollow cathodes is that of supporting NASA missions involving high power electric propulsion. This includes those high power missions, which are envisioned to support human operations in space as well as aggressive space science mission. For example, an energetic ion mitigation method could be directly integrated into the cathode design for the recently proposed Asteroid Retrieval Mission (ARM) which is currently baselined to use 4-5 10 kW Hall thrusters. It should be pointed out that the presence of energetic ions is not germane to high current cathodes though as was observed in the NSTAR long duration test. In this regard, the technology developed from this effort would also eliminate this failure mechanism for cathodes presumably over essentially all operating ranges.
The cathode mitigation technology is generally applicable to Hall and ion thrusters used for both government and commercial satellite orbit raising, orbit transfer, and station keeping. In particular, the mitigation technology supports Air Force and other DoD onboard electric propulsion interests. The technology would also be a life extender for commercial sector satellite makers. Commercial GSO market expects to launch of order 21 satellites per year and commercial NGSO of order 13 launches per year over the next 10 years. Electric propulsion is an onboard propulsion option for these vehicles and in this regard there is a stable market for this cathode life extension technology. The approach investigated here does not constitute a significant modification to the cathode rather it's essentially a retrofit featuring a novel, adaptable technology. This would in turn save costs to satellite venders by reducing development time of long life cathodes based on this technology proposed. More »
The cathode mitigation technology is generally applicable to Hall and ion thrusters used for both government and commercial satellite orbit raising, orbit transfer, and station keeping. In particular, the mitigation technology supports Air Force and other DoD onboard electric propulsion interests. The technology would also be a life extender for commercial sector satellite makers. Commercial GSO market expects to launch of order 21 satellites per year and commercial NGSO of order 13 launches per year over the next 10 years. Electric propulsion is an onboard propulsion option for these vehicles and in this regard there is a stable market for this cathode life extension technology. The approach investigated here does not constitute a significant modification to the cathode rather it's essentially a retrofit featuring a novel, adaptable technology. This would in turn save costs to satellite venders by reducing development time of long life cathodes based on this technology proposed. More »
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| ElectroDynamic Applications, Inc. | Lead Organization |
Industry
Minority-Owned Business
|
Ann Arbor, Michigan |
| Jet Propulsion Laboratory (JPL) | Supporting Organization | FFRDC/UARC | Pasadena, California |
Primary U.S. Work Locations
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California
-
Michigan
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