Schematic of the discharge-cathode assembly.
Pre- and post-test comparison of the DCA following of operation inside of an operating ion thruster discharge chamber.
NCA engineering schematic.
Comparison of the pretest and in-test neutralizer-cathode orifices.
The exterior of the discharge-cathode insert after of operation.
Post-test insert emission surface (left to right) from downstream to upstream end.
Tungsten crystallite formation at the downstream end of the discharge insert.
Discharge insert surface with axial distance from the orifice plate. Lower right image is the unused insert for comparison.
Ba:W ratio comparison for the discharge-cathode insert and control insert to indicate extent of impregnate depletion.
Ba:W signal strength at from the surface as a function of axial distance from the orifice plate for the discharge-cathode insert.
Impregnate depletion depth as a function of axial distance from the orifice plate for the discharge-cathode insert.
Fracture surface of the (top row) downstream end of the discharge cathode and (bottom row) unused insert at 100, 300, and from the surface.
Post-test discharge-cathode tube condition.
(a) Post-test condition of the downstream side of the cathode-orifice plate. (b) Cross-sectional view of the post-test cathode-orifice plate to tube weld with a box indicating the extent of erosion from the pretest condition.
Comparison of (a) post-test and (b) pretest discharge-cathode orifice plate upstream surface. The post-test surface has extensive tungsten deposition in the orifice and on the plate surface.
Post-test condition of the discharge-cathode keeper tube.
Discharge-cathode keeper tube deposition structure.
Cross section of (a) the eroded downstream coil and (b) uneroded coil of the discharge-cathode heater.
Post-test condition of the discharge-cathode low-voltage propellant isolator assembly. Insert in image is the post-test condition of the propellant line screen located downstream of the isolator.
Neutralizer insert surface and subsurface at 100, 350, and from the surface.
Comparison of the Ba:W ratio for the neutralizer insert and an unoperated 4:1:1 insert.
Erosion of the neutralizer-keeper tube on the beam-exposed side.
(a) Post-test neutralizer-keeper orifice indicating. (b) Magnification of keeper orifice deposit structure.
Comparison of the post-test condition of the neutralizer-cathode orifice and chamfer.
Predicted discharge-cathode insert depletion depth.
ELT test segment summary.
Article metrics loading...
Full text loading...