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I know the station's solar panels rotate to track the sun (and also rotate to be in-line with the station for lower drag on night passes), but how does the station itself rotate? I imagine it has to rotate for thermal management issues, or maybe not? I also believe it rotates for docking/supply ship approach, but I'm mostly interested in how it rotates for thermal management. Which axis? What's the rotation rate?

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  • $\begingroup$ Just a quick note that some might find interesting or we get new questions about it, that the rotation of ISS solar panels isn't exactly intuitive since they're double-sided and also capable of generating electric charge from sunlight reflected off the Earth's albedo. And since they're not massless also apply torque on the station's body when rotating, which has to be canceled out. $\endgroup$ – TildalWave Sep 12 '14 at 3:17
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    $\begingroup$ During assembly when there were fewer solar panels, there were several different attitudes held to maximize power output. They are not generally used today. Real time information about the attitude systems is here: spacestationlive.jsc.nasa.gov/displays/adcoDisplay1.html $\endgroup$ – BowlOfRed Sep 12 '14 at 22:31
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Most of the time (when it's not maneuvering for experiments and/or visiting vehicles) the ISS maintains a "fixed" attitude in the noninertial Local Vertical, Local Horizontal reference frame. This means that it rotates about the Y body axis (the "port / starboard" axis) at a rate of one revolution per orbit, about 0.067 degrees per second.

For easier reference, here's the International Space Station’s coordinate system (image credit: NASA):

 enter image description here

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  • $\begingroup$ it's incredibly appalling that they chose the x-axis as forward! as any game engineer will tell you, z is forward! :O $\endgroup$ – Fattie Oct 14 '15 at 16:40
  • $\begingroup$ @Fattie As far as I know, in math and physics, the z-coordinate is the up-coordinate most of the time. But I also did some game programming and seen the other convention. But if I am right, OpenGL and DirectX were also different, one uses a right-handed, the other a left-handed coordinate system. $\endgroup$ – StefanH Jan 3 at 18:00
  • $\begingroup$ @StefanH - please note that I only mentioned Game Development humorously here on the Space site. So it's only a side issue. However, just to clarify I can absolutely, definitely, positively assure anyone reading that in all of game development, "z is forward" - no exceptions. (For example, it's a common thing that you hire a 3D studio or artist to build some component, character, etc, and they forget to do it in z-forward, so you have 'em redo it!) Regarding handedness as you say it annoyingly varies in different apps/ides/engines!!!!! $\endgroup$ – Fattie Jan 3 at 18:06
  • $\begingroup$ (You can find humorous rants from me about the variation-in-handedness online! :) $\endgroup$ – Fattie Jan 3 at 18:09
  • $\begingroup$ @Fattie If the z-forward convention is done wrongly by some artist, I guess it should not pose much trouble to write a script interchanging, or flipping, coordinates. Anyway, just a side issue for sure here :) $\endgroup$ – StefanH Jan 3 at 19:48

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