Kimball Physics Electron Gun Annular Helicon Plasma Source Annular Helicon and Hall Effect Thruster BHT-200 Hall Effect Thruster 9-kW Hall Effect Thruster (H9) Plasma Processes KDC 40 Gridded Ion Source Cylindrical Helicon Gridded RF Thruster T-140 Hall Effect Thruster 10-kW Hall Effect Thruster (T-220HT) Pulsed Inductive Thruster MPD Thruster T-40 Hall Effect Thruster 6-kW Hall Effect Thruster (H6) COMET Dual-Channel Hall Effect Thruster