The question Printer on board of the ISS? was answered in the affirmative. This seems to be a printer with a special paper cassette on "top" to feed the paper, since gravity feed is not going to work. But is it really? Or is that the "receiver" and somebody hid the blank paper cassette which seems to be missing from the bottom?

Has this printer been specially built to work in microgravity? If so, by whom? What kind of printer is it (bubble jet? laser? etc.) Does the ink or toner feed also need special considerations to work in microgravity?

edit: For any piece of equipment to be shipped to the ISS and installed on board, it must go through a significant amount of testing for safety and reliability. So if there is a printer there, then there must be some documented evidence (beyond personal opinion) that it's going to really work reliably - and is not expected to cause problems - in the ISS environment. I think it would be remarkable that an un-modified, off-the-shelf 99 or 49 dollar printer was just put in a launch vehicle, subjected to all sorts of vibrations, then operated in microgravity and reduced pressure in close proximity to humans without any modification. Was it?

Screenshot from the 3D interactive walkthrough from photos by record-holding ESA astronaut Samantha Cristoforetti taken in June 2015

printer on the international space station?

Zoomed and rotated from here (printer on lower-left):

enter image description here

"Reblogged" from @ForgeMonkey 's answer


  • $\begingroup$ So, with all the added cost and hassle of printing in zero g, the difficulty of getting ink into space and so forth, the ISS isn't totally paperless? I'd take a kindle in space over paper any day. Anyone know WHY there is a printer? $\endgroup$
    – wedstrom
    May 31, 2016 at 21:50
  • 6
    $\begingroup$ @wedstrom I think it's used for printing out boarding passes for the flight home. You know, with increased security and all these days. $\endgroup$
    – uhoh
    Jun 1, 2016 at 3:12
  • 2
    $\begingroup$ @wedstrom -- Whenever I'm working on a computer, I have at least two of four very old-fashioned devices right next to the computer: A green engineering pad and/or my unlined Moleskine notebook, and a very nice mechanical pencil and/or a very nice pen. When I'm debugging the blank sheet of paper, I want a blank sheet of paper rather than a computer facsimile of one. $\endgroup$ Jun 1, 2016 at 18:06
  • 5
    $\begingroup$ @DavidHammen I'd think twice about that workflow if notebook paper was $10,000 a kilogram... $\endgroup$
    – wedstrom
    Jun 1, 2016 at 18:58

3 Answers 3


It's an Epson Stylus Color 800 - a pretty standard inkjet printer (a laser printer would be a nightmare - all that fine toner dust!)

Here's an example of an Earthly one from a 1998 page of the Washington Apple Pi Journal:

enter image description here

The ink cartridges don't care about gravity - they work by capillary attraction from a storage sponge in the cartridge, and then vaporisation at the print head. You can run print heads at whatever angle you like here on Earth, and they work just fine in microgravity, but some optimisation could have been carried out, as per this paper from RIT.edu. That optimisation is for drop speed, size and shape, and not essential for operation.

The only challenging bit is the paper feed, as it is usually gravity fed from the top, letting the paper sit in place until the pickup and feed rollers are in use. The roller friction itself is sufficient once the paper is pulled into the feed path, but without gravity this may not work - compare the two pictures to see the additional section which feeds the paper in the absence of gravity.

To answer the actual question:

The printer was not built specifically for space, but there are modifications to ensure it works in space. The obvious one being the paper feed unit, but others are likely, such as optimisation of print heads and strengthening of ribbon cables etc to cope with the vibration of launch.

  • $\begingroup$ OK - So is the paper feed a specially designed modification for microgravity? If so, can I read about it somewhere? Is Epson 800 coming from the Quora answer by Robert Frost, or do you have a better source? Also, can I have some link to a source for the statement that standard Epson ink cartridges work in microgravity and zero gravity? Capillary action works well in capilaries, but what about the reservoir holding the floating globule of ink? I mean in order to drink the fresh-brewed espresso on the ISS they had to use specially designed cups. $\endgroup$
    – uhoh
    May 31, 2016 at 14:27
  • $\begingroup$ @uhoh Well, they certainly have something non-standard covering the paper feeder, at least. No telling from the picture what that does, though. $\endgroup$
    – user
    May 31, 2016 at 14:37
  • $\begingroup$ Thanks - I've added an edit to the question. The info on the sponge was interesting (someone has removed several comments without a trace or explanation) but I need an independent source that shows that they really do work in microgravity - ind if they do with, or without modification. $\endgroup$
    – uhoh
    May 31, 2016 at 15:25
  • $\begingroup$ There are no floating globules. The ink permeates a sponge in the cartridge, as anyone who has used a refill kit can tell you. $\endgroup$ May 31, 2016 at 15:41
  • 1
    $\begingroup$ @JerardPuckett (and Rory) I found this hpinkcartridges.co.uk article about the sponges. So it's also the hydrophobicity of the "sponge" material, not just capillary action that "pushes" the ink out. The second image is pretty darn dramatic - showing the black ink crowding down towards "EXIT" while the remainder of the sponge as totally dry and free of any ink. Nice! I'm on vacation - as soon as I get some I'm going to pop a few open! $\endgroup$
    – uhoh
    May 31, 2016 at 18:32

There are no modern printers with gravity fed paper input. The paper is always "picked" by a roller on a bar that is mechanically pressed against the paper. Output is the problem. Printers rely on gravity to hold the paper in the output tray. The ISS printer is modified to enclose the output trays. The input tray is also enclosed because the roller pressure is intentionally weak on top loaders until the printer performs a paper feed. This allows users to add paper easily. Older inkjet cartridges used sponges, newer ones use fiber. The cartridge fiber is saturated with ink when new, there is no ink sloshing around in the cartridge. Canon and HP inkjets use heat to shoot out ink drops, Epsons use piezoelectric squirt guns.

  • $\begingroup$ That's a good point - probably easier to make hydrophobic fibers than a hydrophobic sponge! I wonder if they are still referred to "sponges" even though they're made from fiber. I wish someone would post something like this image from hpinkcartridges.co.uk so everyone could see what this whole ink in microgravity discussion is about! $\endgroup$
    – uhoh
    Jun 1, 2016 at 1:09

My brother just pointed out that:

In October 1998, the Epson Stylus Color 800 became the first ever color printer to be used in space when it was installed in the Space Shuttle Discovery for the 92nd space shuttle mission (STS-95). The printer performed so well that Epson was subsequently selected as the printer supplier for the International Space Station.


enter image description here


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