As we know, cars need a front window because drivers need to see the road to control the car, but how about the windows in space shuttles? As far as I know, the orbits of ISS or other space devices are mostly controlled by a computer, not by humans directly.

Is it just to allow people in space look back to Earth so that they don't feel bored? Or do the windows have other uses?

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    $\begingroup$ Not sure if it was true to the actual mission, but the Apollo 13 movie showed the crew looking out the window to see the venting gas, and later to use the Earth as a visual cue for steering during a burn. If either of those is true, then windows sure come in handy once things go wrong. $\endgroup$ – Andrew Thompson Nov 1 '16 at 6:25
  • $\begingroup$ @AndrewThompson Apparently it was the hatch, not the window; not sure how that works. apollo13.spacelog.org/02:08:09:07/#log-line-202147 GET 02:08:09:07. apollo13.spacelog.org/03:00:28:54/#log-line-260934 at GET 03:00:28:54 they specifically discuss the sun check through the alignment optical telescope (AOT) for alignment verification before the mid-course to put the spacecraft back on a free-return trajectory, see for example 03:00:37:39. I haven't double-checked the MCC depicted in the movie against the mission transcript. See also hq.nasa.gov/alsj/a13/AS13_TEC.PDF. $\endgroup$ – user Nov 1 '16 at 8:51
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    $\begingroup$ @Gstestso The question title and body are a little ambiguous. Are you asking specifically about glass windows, or are you asking about windows in general? Glass would, at first glance, appear to be a poor choice of material for a window on a spacecraft. $\endgroup$ – user Nov 1 '16 at 8:53
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    $\begingroup$ Shuttle windows were glass. @MichaelKjörling what would you expect them to be made of? science.ksc.nasa.gov/shuttle/technology/sts-newsref/… $\endgroup$ – Organic Marble Nov 1 '16 at 13:38

For shuttle, the crew flew the last few minutes of the landing manually. Manual flying was a contingency mode for most parts of the entry. Some kind of outside view is required for that. Given video technology in the 70s when shuttle was designed, they went with windows.

The aft and overhead windows were important for robotic arm and docking operations. Camera views were used as well but window views were often crucial.

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Video technology of the MIR space station was obviously still not good enough during the 1997 MIR-Progress collision. The radar had been shut down because of technical problems, but the docking attempt was ordered to go ahead anyway, by a crew member remotely operating the approaching Progress supply spacecraft via a video monitor

Just afterwards, in the power outage caused by the collision (they had to cut the main power cable in order to close the door to the punctured module to save the breathable indoor atmosphere and survive):

"So, in the dark and in the silence, [astronaut Mike] Foale went to the windows in the airlock and held his thumb up to the field of stars. Combining a sailor’s technique with a scientist’s knowledge of physics, Foale estimated the spin rate of the space station." Dramatization of the event.

So at least as late as 1997 windows played a useful role in helping determine the rotation, and I suppose thereby determining the Earth communication and solar power periods of a crewed space station.


I would like to add one additional effect. Keeping the astronauts sane. Really, ever sit in a small tight room for a week with no windows and no confirmation of anything beyond. In prison they use that as a punishment. Just the ability to look out and confirm that you "can" go there, and you don't "have to" live the rest of your life in this little tin can, is an amazing effect.

Try taking a cruise, and getting a small cabin with no window, then nit being allowed to leave that small cabin on penalty of death. You's do pretty much anything to have a tiny window to look out of.

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    $\begingroup$ Submariners routinely go without sunlight or a view out for months at a time. I'd expect astronauts to have that ability as well. $\endgroup$ – Hobbes Nov 2 '16 at 16:45

On the ISS, the Cupola is used to observe operations:

The International Space Station Cupola was first conceived in 1987 by Space Station Man-Systems Architectural Control Manager Gary Kitmacher as a workstation for operating the station’s Canadarm2 robotic arm, maneuvering vehicles outside the station, and observing and supporting spacewalks. He likened the use as similar to that of the Shuttle Orbiter Aft Flight Deck.

I wouldn't dismiss giving the astronauts a window to look out of as unimportant. Several astronauts I've heard speak, said the most profound change they went through was in the way they look at Earth: they came to understand how fragile Earth's society and ecosystem is, and how rapidly the ecosystem is changing for the worse.

Source for the last paragraph: a 3-hour talk by astronaut André Kuipers, almost half of it was spent sharing his observations of Earth and the changes he's seen between 2 missions ~10 years apart. Some changes are obvious to the naked eye, others can be easily seen if you have 2 photos of the same region taken at different times.

More examples:

Chris Hadfield:

Orbiting Earth 2593 times, what I really came to appreciate was the commonality of the human experience. From orbit you see the repeated patterns of human settlement and civilisation, and inevitably start to sense that each of us inherently wants the same things out of life - joy, grace, time and stability to think, better opportunities for our children, laughter, someone to love. The precept of 'Us' and 'Them' is one that is taught; it's not the fundamental reality. Seeing the whole world as 1 place every 92 minutes drove that home within me, forever.

Edgar Mitchell:

You develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, "Look at that, you son of a bitch."

Tim Peake:

The view of Earth is the biggest thing, and it is probably the thing that has the biggest impact on you, so it is quite natural that is the thing you will miss the most

André Kuipers:

From up here I can see humanity’s footprint, including forest fires, air pollution and erosion

Example photo taken from the ISS of the Amazon rainforest. Dark green = rainforest. Lighter colors = forest chopped down to be replaced with agriculture.


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    $\begingroup$ "they came to understand how fragile Earth's ecosystem is and how rapidly it's changing for the worse." -- yeah, you can't see that out the window. $\endgroup$ – Malvolio Nov 1 '16 at 21:08
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    $\begingroup$ You certainly can, if you know what you're looking for. $\endgroup$ – bright-star Nov 2 '16 at 3:54
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    $\begingroup$ @Malvolio You can't see it out of your window. When the window is 400 kilometers up, that helps a lot. $\endgroup$ – Williham Totland Nov 2 '16 at 8:00
  • $\begingroup$ Here is the view from ISS. Point out where you see the fragility or lack thereof in the Earth's ecosystem. $\endgroup$ – Malvolio Nov 2 '16 at 9:42
  • $\begingroup$ See this photo for example: earthobservatory.nasa.gov/IOTD/… $\endgroup$ – Hobbes Nov 2 '16 at 11:15

Windows have been primarily required for

  • Docking operations (Gemini, Apollo CM and LM, STS, ISS)
  • Landings (Apollo LM, STS)
  • Remote manipulation, e.g. Canadarm (STS, ISS)
  • Visual inspection (Apollo, STS, ISS)

We're still not at a point where every last thing is automated or instrumented, and some manual intervention and inspection is still necessary. Not to mention that instruments occasionally fail, and having a Mark I Eyeball as a backup is not a bad thing.

And do not discount the psychological value of having a window. I've worked in offices with and without windows, and just having a bit of natural light filtering in can make a huge difference in mood and productivity. Yes, astronauts should have the psychological stamina to be able to work in closed spaces for extended periods of time, but if having a window makes it easier for them to do their jobs, then why not have one?


Other people have already pointed out practical reasons for being able to see outside; for controlling robot arms, landing shuttles manually or general failover. Cameras are not only more fragile, but much more complex and expensive than a simple window (camera + monitor + camera controls + cable management through the outer wall of the vehicle + power usage, and so on). There is nothing particularly difficult about replacing a section of wall with a window, on the other hand. We do it in industrial settings all over the place (glasses for high pressure, high temperature apparatusses etc.).

Is it just to allow people in space look back to Earth so that they don't feel bored?

But let me stress that you can easily leave out the word "just" in this sentence, and will hit at least part of the truth right on the head.

The "people in space" are not just circumstantial, but they are the most important part of any manned (sic) space program. I don't have numbers, but I'd wager that the cost of selection, training, life support systems etc., make a great, if not huge part of the overall cost (both money and time) of manned spaceflight.

Hence, even if there were no other reasons, the relatively minor cost of adding a few windows might offset huge costs for otherwise necessary measures to keep the humans on the ISS sane. Keep in mind that other things are also done "just" to keep the astronauts happy. Like a small weight allowance to bring personal stuff like music instruments and the like. If that were not a psychological necessity, you can be sure that it would not happen.

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    $\begingroup$ Cameras have another drawback: with a window, you have depth perception. To replicate that with cameras has only recently become possible, and even now it's difficult to avoid nausea because a VR monitor system causes dissonance between what you see and what your inner ear tells you. $\endgroup$ – Hobbes Nov 2 '16 at 19:52
  • $\begingroup$ But the depth perception looking through the window has its limits, it works well for distances of some meters, but not for the distance from a LEO to the earth surface below. $\endgroup$ – Uwe Dec 9 '16 at 14:40

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