“…In one life test, the cathode cover eroded completely away, although the cathode continued operating. Recent thruster designs at the 20 -40 kWe level are for 15,000 h. 6,9 Scaling to high power The majority of power input to ion thrusters is deposited in the exhaust beam, so that P e ~ j b A g V b . J b is the ion current flux through the grids, A g is the grid area, and V b is the voltage to which the ions are accelerated.…”