I was looking at the NASA image of the day today, and it made me wonder about the windows on the ISS. I often see pictures of Earth taken from the ISS, but I was wondering if they had any windows that looked "up", towards zenith, opposite to Cupola with windows facing "down", towards nadir.

I don't think I've ever seen any pictures taken of space or the Moon (except when they captured the Moon near the horizon of Earth) from the ISS. Do they have anything looking in that direction?

  • $\begingroup$ I'll match @RoryAlsop 's bounty if it's awarded (and if the issue is clearly resolved and the ambiguity removed of course). I can't tell which of the highly up-voted answers says "yes" and which says "no", but I'd sure like to see a photo of the zenith side of the ISS from outside that shows if it (a zenith-facing window) exists or not! $\endgroup$ – uhoh Jun 19 '17 at 8:08
  • $\begingroup$ BTW, can aft-docked Soyuz have a zenith-facing window? $\endgroup$ – SF. Jun 20 '17 at 15:32
  • $\begingroup$ @duzzy I've just asked Has the ISS ever “flown upside down”? Has the cupola ever “looked up”? $\endgroup$ – uhoh Apr 3 at 3:08

There are windows on Zvezda from which you can see zenith, but these aren't facing exactly zenith. It doesn't seem as though any other segment on the ISS have zenith windows.

From this website, at the bottom there are attachments that show the various cross-sections for Zvezda. It's a little confusing, however, since this imagezenith cross section has the +x and +z labelled as though you were looking at it from the +y direction, not from zenith. Based on actual photos of Zvezda, however, this image is indeed zenith. As you can see, windows 12 and 13 on the neck of the craft are pointed at a 45 degree angle towards zenith. 3D model of Zvezda This 3D model of Zvezda shows the two closed windows, on the neck near the orange circle. You can clearly see window 12 facing at an angle towards space.


This is the best actual image I could find of Zvezda in space (it proves we are looking at the correct side), but unfortunately the view of the windows are obstructed by the body of the craft.

I found this picture Far away which is the correct angle, but it's difficult to see the window. If you zoom in, you can, however, barely make it out. It's covered and just looks like a circle.

So in conclusion, it doesn't look like there are any windows facing exactly zenith, but there are two that angle in that direction.

  • $\begingroup$ Thanks for the new images! It's good to call it an inclined window that may have a view of the zenith, but it's not a zenith-facing window because zenith-facing means the direction that the window faces is the zenith. This window faces some complicated direction that looks to me like even more than 45 degrees away from the zenith. So there's just this one? Number 2 is not facing up? Which number is this one? Thanks! $\endgroup$ – uhoh Jun 21 '17 at 21:32
  • $\begingroup$ @uhoh I don't know why you think it's facing more than 45 degrees. In the last picture I showed, I believe the station isn't at normal orientation, the normal orientation would be like the second to last picture. As for the second window (window 13), I think it's still there, but we can't see it easily from any of the pictures. The one we can see is window 12. $\endgroup$ – Arthur Dent Jun 21 '17 at 21:44
  • $\begingroup$ The orange circle is nominally facing zenith, and the windows are 45 degrees on either direction from that circle's normal, as you can see in the 3D model and in the last picture. I would like to add a circle to highlight where exactly the window is, but I don't know how to do so. $\endgroup$ – Arthur Dent Jun 21 '17 at 21:46
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    $\begingroup$ @uhoh My answer does say exactly what you suggested, that you can see zenith from the windows but they don't point exactly zenith. $\endgroup$ – Arthur Dent Jun 21 '17 at 22:05
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    $\begingroup$ nope - I'm very happy with this answer. It meets all my requirements for the bounty. I'm not sure what it is you want from questions, sometimes, but I am satisfied by this. $\endgroup$ – Rory Alsop Jun 27 '17 at 15:22

The RSC Energia has recently published a study on the effect of high-velocity impacts of meteoroids and space debris on glass windows of the ISS in their "Kosmicheskaya Tekhnika i Tekhnologia" quarterly journal.

At page 55 they have a nice three view scheme of Zvezda windows locations with the sizes, directions and angles specified:

Location of Zvezda service module windows

Figure 1. Service module windows (location, Type):

1 — TSK.316.02.000 (∅228); 2 — TSK.316.02.000; 3 — TSK.316.02.000; 4 — TSK.316.03.000;
5 — TSK.316.02-1.000; 6 — TSK.316.02-1.000; 7 — TSK.316.02-1.000; 8 — TSK.316.02-1.000;
9 — TSK.316.01.000 (∅426, uncoated); 12 — TSK.316.02.000; 13 — TSK.316.02.000;
14 — TSK.316.02.000; 26. — TSK.316.03.000 (∅80);

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    $\begingroup$ +Z is zenith, -Z is nadir? $\endgroup$ – Hobbes Jun 28 '15 at 20:14
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    $\begingroup$ @Hobbes it seems to be the opposite, +Z is the nadir, down, "deck" direction. Helpful discussions and graphics here and here and here. $\endgroup$ – uhoh Jun 19 '17 at 6:13

There are many windows on the ISS. Destiny (The US Lab, between Node 1 and Node 2) has a 20 inch window facing Earthwards.

The Russian segment has several, and they have covers to protect them when not in use.

Zvezda is the key module for windows:

Zvezda has 14 windows— There are two 9-inch-diameter (230 mm) windows, one in each of the two crew sleep compartments (windows No. 1 and 2). Six 9-inch-diameter (230 mm) windows (No. 3, 4, 5, 6, 7 and 8) on the forward Transfer Compartment earth facing floor. As well a 16-inch-diameter (410 mm) window in the main Working Compartment (No. 9) and one 3-inch-diameter (76 mm) window in the aft transfer compartment (No. 10). There are a further three 9-inch-diameter (230 mm) windows in the forward end of the forward transfer compartment (No. 12, 13 and 14), for observing approaching craft. Note: Window No. 11 is unaccounted for in all available sources.

The US segment has some windows, but the primary viewing location in the Cupola, which is attached to Node 3, which faces off the main line of the station. The Cupola is facing down, (nadir) towards the Earth, but it has a main window facing out, and a series of windows around the edge.

Thus you could look over the limb of the Earth to see space.

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    $\begingroup$ The additional detail was helpful, thanks. +1 from me. $\endgroup$ – called2voyage Jun 26 '15 at 18:07
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    $\begingroup$ Now whatever happened to window #11? $\endgroup$ – kim holder Jun 26 '15 at 19:14
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    $\begingroup$ @briligg stargate.wikia.com/wiki/Quantum_Mirror ;) $\endgroup$ – called2voyage Jun 26 '15 at 19:34
  • $\begingroup$ @called2voyage gonna start working on a follow-up question... $\endgroup$ – uhoh Jun 19 '17 at 6:08
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    $\begingroup$ @kimholder we don't talk about window #11... not since the war... $\endgroup$ – Sarah Bailey Jun 19 '17 at 16:52

Very late to the party, but here's a supplemental answer supporting the argument that Service Module (SM) windows 12 and 13 can be used to view the zenith.

Images generated by DOUG, an official NASA JSC visualization software used in mission planning and crew training. Available to the general public for free!

This shows the location of SM window 12. I highlighted the foot restraint above it (in the zenith direction) in gold as shown.

enter image description here

This shows the view out of the window looking zenith-wards. You can see the gray Strela crane and just a bit of the gold foot restraint.

enter image description here

This shows the location of SM window 13. I highlighted some Russian gadget called BKDO above it (in the zenith direction) in gold as shown.

enter image description here

This shows the view out of the window looking zenith-wards, including the BKDO.

enter image description here

  • $\begingroup$ I hadn't seen this until today, very interesting! Real world pressure windows have a substantial thickness and are usually surrounded with thick flanges for the bolts. These will become problematic when the window diameter is small and the viewing angle highly oblique. My guess is that in this model, the window is simply a hole in an infinitely thin surface, so I'm not sure this demonstrates that one could actually view the zenith by placing a human head next to the window and trying to look through. Out of curiosity does the software provide the angle between the zenith and the window normal? $\endgroup$ – uhoh Jan 26 at 4:17
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    $\begingroup$ @uhoh there is no data readout like that as far as I know. The user just selects the window of interest from the Assign Window View menu and the resulting eyepoint is placed wherever the developers thought it should be for a person looking out the window. You can pan and tilt the view; if you go too far, it shows the window frame. $\endgroup$ – Organic Marble Jan 26 at 14:23
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    $\begingroup$ @uhoh just fyi when using "window views" the user can't translate the eyepoint, only rotate, pan and tilt it without limit. when using "camera views" the user can only pan and tilt to the extent the camera mount allows and also can't translate or rotate. There are free-flying eyepoints available where you can pan, tilt, rotate and translate freely. $\endgroup$ – Organic Marble Jan 26 at 14:29
  • $\begingroup$ Okay got it! I see there's a way to request download via secure email, I wonder if this will end up being like What does it mean when a software is called open-source for US-release only? or How open is NASA's “open source” GMAT software? $\endgroup$ – uhoh Jan 26 at 14:33
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    $\begingroup$ @uhoh if you are able to acquire it, there's a useful page with downloadable "flight packages" where the configuration of the iSS is kept current. vrlab.jsc.nasa.gov $\endgroup$ – Organic Marble Jan 26 at 14:39

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