This answer estimates that the DAWN spacecraft's solar-electric propulsion accelerated about 3 milligrams of Xe+1 per second, using roughly 1350 Watts of electrical power. I estimate that 3 mg/sec of Xe+1 should be about 2.2 amps, so the acceleration potential might be in the ballpark of 600 volts.

Is the choice of voltages near 1 kilovolt the result of some optimization in kinematics? If so, can it be explained quantitatively with a simple mathematical model? Would say 200 or 2000 volts have both resulted in poorer use of the available

  1. solar-electric power?
  2. propellant?
  3. time?
  • $\begingroup$ potentially helpful answer and there good information in this paper about DAWN's engine progenitor: Performance of the NSTAR ion propulsion system on the Deep Space One mission that may be helpful as well. $\endgroup$
    – uhoh
    Commented Apr 15, 2020 at 4:18
  • $\begingroup$ You might want to change your estimations to the actual numbers you found in the paper you linked: 1100V, 1.76A, 23.43sccm $\endgroup$
    – asdfex
    Commented Apr 15, 2020 at 10:21
  • $\begingroup$ @asdfex ya I've just used the results of the previous answer to make an estimate for DAWN, and the paper I mentioned in the comment is for NSTAR. $\endgroup$
    – uhoh
    Commented Apr 15, 2020 at 10:50
  • 1
    $\begingroup$ With limited power high voltage means low current, low particle flow, and mass flow, and low thrust, unless you switch to a heavier particle. $\endgroup$ Commented Apr 15, 2020 at 19:50
  • 1
    $\begingroup$ "The ion thrusters for Dawn are identical to the DSI flight thrusters.". Brophy et al. in The ion propulsion system for DAWN, 2013 $\endgroup$
    – asdfex
    Commented Apr 17, 2020 at 7:52


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