This tweet from Expedition 51/52 astronaut Jack Fischer admires the great view straight down from the ginormous Russian porthole of the Progress cargo vehicle on the ISS.

I don't really understand where this porthole is. Is it the porthole part of a docked spacecraft, or is it a permanent part of the ISS?

Is this the same direction that the center, round window of the ISS's Cupola faces?

enter image description here

enter image description here

enter image description here

  • 3
    I'm also curious why this porthole is covered, then covered again (with some misc equipment inside that second cover)... – Steve Jul 26 '17 at 16:36
up vote 13 down vote accepted

It's on one of the Russian modules of the ISS, that's why it's a ginormous Russian porthole. Since the porthole is facing Earth, I'd say yes, it's also facing the same general direction as the cupola, but not necessarily the same exact direction.

@Steve the first cover is part of the pressure containment vessel of the station, note the mating seals around its rim and the seat of its closed position. If the glass of the porthole cracks or otherwise starts leaking, the first cover keeps the air in the station from all rushing out. The other cover is the access hatch in the inner walls of the ISS that define the bounds of normal day-to-day operation.

The opinions expressed in this analysis are my own, YMMV.


It's window number 9 (of 14) in the Zvezda module, a 16-inch-diameter (410 mm) window in the main Working Compartment. (N.B. Window No. 11 is "unaccounted for in all available sources" - so it's quite possible there are only 13 windows on the module.)

Russian Space Segment windows
Russian Space Segment windows, from Wikipedia
link to full size (1096 x 823) image

I guess "ginormous" is a matter of opinion - a 16 inch window doesn't seem to be that big - from here on the ground.

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.