This one sentence nearly link-only answer to What is the principle behind Mariner 4's “Solar Pressure Vanes”? In what case(s) would they be effective? and the discussion below explain that Mariner 4 (and I think 3) used four articulated paddles that were black/absorbing on one side and white or shiny (reflective) on the other to produce torques on the spacecraft to (if I understand correctly) remove any residual rotation after thrusters were used to change spacecraft attitude.

I'm guessing that this is because these mid 1960's spacecraft didn't have reaction wheels or if they somehow did, didn't want to rely on them.


  1. Were Mariner 3 and 4 the only spacecraft to use articulated "solar paddles" to stabilize or otherwise affect attitude? Or has this been used previously or since?
  2. What was the nature of the coatings on the panels? Black paint vs white paint, or did was the reflective side more specular in nature? The image suggests both sides might be dark so perhaps I don't understand at all how they are used!


Mariner 4 (3 similar)

Mariner 4 (3 similar) nssdc.gsfc.nasa.gov

Source (nssdc.gsfc.nasa.gov 1964-077A)

Mariner 5

Mariner 5 nssdc.gsfc.nasa.gov 1967-060A

Source (nssdc.gsfc.nasa.gov 1967-060A

  • 1
    $\begingroup$ The Kepler telescope used radiation pressure to stabilize its attitude once it was down to two reaction wheels (hence the K2 mission). But as this approach was used out of necessity rather than by design, I doubt it had "articulated solar panels". $\endgroup$ Jun 21, 2021 at 20:10
  • $\begingroup$ @CharlesStaats That's right! I think there can be a future question about more generalized uses of solar pressure. JWST gets a lot of pressure from it's giant solar reflector and puts it to good use as well. But for this question I'm just asking about doing things they way they did for these two Mariners. $\endgroup$
    – uhoh
    Jun 22, 2021 at 1:09


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