Astronatix's SPT-100 lists the following:

Stechkin electric rocket engine. Used on Meteor and Gals satellites.

  • In Production. 1.35 kW Hall thruster.
  • Thrust variable 2 to 20 kgf.
  • Marketed in USA by Space Systems/Loral and Fakel.
  • Status: In Production. Date: -1984.
  • Thrust: 196 N (44 lbf).
  • Specific impulse: 2,500 s. Specific impulse sea level: 800 s.
  • Electrical Input Power: 1.35 kW.

Question: How does a conventional (looking) Hall effect ion thruster have a sea-level Isp of 800? Can it really operate at atmospheric pressure?

Also: Isn't 196 Newtons about 1000x larger than what you might expect?

Stechkin 1.35 kW Hall thruster


The SPT-100 thruster is described along with several others in the paper: Electric Propulsion Activity in Russia; IEPC-01-05, Presented as Paper IEPC-01-(05) at the 27th International Electric Propulsion Conference, Pasadena, CA, 15-19 October, 2001.

Table 2 lists its specifications:

Nominal operation mode power, kW: 1.35

Nominal thrust, mN: 80

Specific impulse, s: 1600

It seems plausible that the Russian paper (and NASA) are more correct that the Astronatix site.

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    $\begingroup$ I meant more-correct than the Astronatix site; I've made an edit. $\endgroup$ – Roger Aug 8 '19 at 19:34
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    $\begingroup$ Excellent! Thank you for tracking this source down.I think it's pretty obvious now that the Astronautix article is simply wrong. $\endgroup$ – uhoh Aug 8 '19 at 22:23

Can't speak to the sea level Isp (other than agreeing with your intuition that it's bogus), but the thrust is clearly in error.

NASA testing of the engine in 1993 showed < 100 mN thrust in vacuum, with associated Isp's between 1000 and 2000.


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    $\begingroup$ I wonder if this entry started as a copy/paste from another engine and someone simply forgot to edit the text? $\endgroup$ – uhoh Aug 8 '19 at 14:18
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    $\begingroup$ The power use and vacuum Isp seem roughly consistent with what's in the NASA paper, so no idea. $\endgroup$ – Organic Marble Aug 8 '19 at 14:22

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