# What Operating System does the Space Station use? **URL:** \ **Category:** Factual Questions\ **Created:** [July 18, 2009, 3:18pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440 "2009-07-18T15:18:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![AndrewJRichards](https://avatars.discourse-cdn.com/v4/letter/a/7ea924/32.png) [@AndrewJRichards](https://boards.straightdope.com/u/AndrewJRichards)\ **Post date:** [July 18, 2009, 3:18pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/1 "2009-07-18T15:18:51Z")
Cecil stated in his most recent column: “Windows is so notoriously unreliable that no one would ever build a life-or-death system around it.” My question is what operating system does the International Space Station use? I’ve found articles that imply it uses [Windows](http://www.appletell.com/apple/comment/international-space-station-windows-computers-infected-with-virus/) and [Linux](http://www.linuxjournal.com/article/3024), but I’m not sure. Also, is Cecil right in stating that no “life-or-death” system has been built around Microsoft Windows? Banks? Hospitals? The military? ---
**Author:** ![BrandonR](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@BrandonR](https://boards.straightdope.com/u/BrandonR)\ **Post date:** [July 18, 2009, 3:30pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/2 "2009-07-18T15:30:12Z")
Lots of systems use and run on Windows in industry. It’s just that, for many applications, it’s overkill and overly complicated. That’s why most “computers” like ATMs and the like run on very basic Linux-esque operating systems that are purpose-driven. As for what operating system a space station uses, I doubt there’s just one running the entire thing. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [July 18, 2009, 3:44pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/3 "2009-07-18T15:44:41Z")
Linux? You mean unix don’t you? What code behind? Fortran? For navigation and comunication I would suspect unix. Day to day stuff I would bet on windows XP pro. It aint’ Vista. They have come back. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [July 18, 2009, 3:49pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/4 "2009-07-18T15:49:19Z")
Whatever OS it is, I bet it’s _outta this world!_ [sub]Sorry. I’ll come in again.[/sub] ---
**Author:** ![Waffle\_Decider](https://avatars.discourse-cdn.com/v4/letter/w/77aa72/32.png) [@Waffle\_Decider](https://boards.straightdope.com/u/Waffle_Decider)\ **Post date:** [July 18, 2009, 3:59pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/5 "2009-07-18T15:59:01Z")
For the really important stuff, they may have just written everything from scratch themselves instead of using something off the shelf. I don’t know about the ISS, but I believe this is the case for the Space Shuttle, where every single line of the flight control software is very carefully reviewed and audited. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [July 18, 2009, 3:59pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/6 "2009-07-18T15:59:07Z")
I doubt that most of the Space Station has much of anything like an OS. It’s more wired like your garage door or something. There might be an actual, all-purpose computer with on it, and that could be Windows or anything, but I suspect that it isn’t an integral part of the overall station. If there is an OS for any major part of the station, it might be one of: > **[LynxOS](https://en.wikipedia.org/wiki/LynxOS)** > > The LynxOS RTOS is a Unix-like real-time operating system from Lynx Software Technologies (formerly "LynuxWorks"). Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility. LynxOS is mostly used in real-time embedded systems, in applications for avionics, aerospace, the military, industrial process control and telecommunications. As such, it is compatible with military-grade security protocol such as wolfSSL, a popular Transpo Th... > **[VxWorks](https://en.wikipedia.org/wiki/VxWorks)** > > VxWorks is a real-time operating system (or RTOS) developed as proprietary software by Wind River Systems, a subsidiary of Aptiv. First released in 1987, VxWorks is designed for use in embedded systems requiring real-time, deterministic performance and, in many cases, safety and security certification for industries such as aerospace, defense, medical devices, industrial equipment, robotics, energy, transportation, network infrastructure, automotive, and consumer electronics. > VxWorks supports ... > **[ThreadX](https://en.wikipedia.org/wiki/ThreadX)** > > Azure RTOS ThreadX is a highly deterministic, embedded real-time operating system (RTOS) programmed mostly in the language C. > ThreadX was originally developed and marketed by Express Logic of San Diego, California, United States. The author of ThreadX is William Lamie, who was also the original author of the Nucleus RTOS in 1990. William Lamie was President and CEO of Express Logic. > Express Logic was purchased for an undisclosed sum by Microsoft on April 18, 2019. > The name ThreadX is derived f... > **[Integrity (operating system)](https://en.wikipedia.org/wiki/Integrity_(operating_system))** > > INTEGRITY and INTEGRITY-178B are real-time operating systems (RTOSes) produced and marketed by Green Hills Software. > INTEGRITY is POSIX-certified and intended for use in embedded systems of 32-bits or 64-bits. Supported computer architectures include variants of: ARM, Blackfin, ColdFire, MIPS, PowerPC, XScale, and x86. INTEGRITY is supported by popular SSL/TLS libraries such as wolfSSL. > INTEGRITY-178B is the DO-178B–compliant version of INTEGRITY. It is used in several military jets such as t... > **[PikeOS](https://en.wikipedia.org/wiki/PikeOS)** > > PikeOS is a commercial, hard real-time operating system (RTOS) that offers a separation kernel based hypervisor with multiple logical partition types for many other operating systems (OS), each called a GuestOS, and applications. It enables users to build certifiable smart devices for the Internet of things (IoT) according to the high quality, safety and security standards of different industries. For safety and security, critical real-time applications on controller-based systems without memory ... Or any other one of several available [Real-Time Operating Systems](http://en.wikipedia.org/wiki/Real-time_operating_system), or a homegrown variety. And possibly there are several systems each using a different OS, just depending on who developed that component and which OS they had experience with, or happened to find the homepage of first. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 18, 2009, 4:06pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/7 "2009-07-18T16:06:10Z")
There are space certified versions of linux out there. NASA also uses specialized embedded operating systems that desktop users have likely never heard of, like VxWorks, ThreadX and QNX. NASA also has some proprietary operating systems that they themselves have developed, which only run on their equipment. Usually NASA contracts to another company to make subsystems, and it is up to that subsystem vendor to put whatever OS they deem suitable into the thing. NASAs specs are pretty tough, though, and Windows isn’t reliable enough to meet them. NASA does use windows on desktop computers, but they don’t run space equipment with windows. I design industrial control systems for a living, and my company currently uses its own proprietary operating system. We are considering porting to linux. We evaluated moving to windows (there are embedded versions of windows out there) but we found its real time performance to be so poor as to be unusable for our purposes. Linux and VxWorks are your two biggest players in the real time control arena. Microsoft gets a lot of use in the HMI (human-machine interface) because windows is good at GUIs, so while the control panel might be windows, the part that does the real work is not. Banks are not “life or death” and you’ll often find windows based systems in them. It’s kinda funny to see an ATM with a blue screen of death. Hospital equipment, like NASA equipment, uses whatever the equipment vendor decided to put in there. If the machine has an HMI then it might be windows. If the equipment is truly life or death critical, it’s almost guaranteed not to be running windows. ---
**Author:** ![CaveMike](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cavemike/32/16379_2.png) [@CaveMike](https://boards.straightdope.com/u/CaveMike)\ **Post date:** [July 18, 2009, 4:07pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/8 "2009-07-18T16:07:52Z")
> [@BrandonR](#): > > Lots of systems use and run on Windows in industry. It’s just that, for many applications, it’s overkill and overly complicated. That’s why most “computers” like ATMs and the like run on very basic Linux-esque operating systems that are purpose-driven. This isn’t as true today as it used to be. Windows XP Embedded shows up in a lot of unexpected places. I believe it has a strong presence in ATMs as well as gaming (gambling) machines. Occassionally pictures show up of Windows Blue Screen on embedded devices like ATMs. Probably by now these is a whole site dedicated to these type of pics. ---
**Author:** ![CaveMike](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cavemike/32/16379_2.png) [@CaveMike](https://boards.straightdope.com/u/CaveMike)\ **Post date:** [July 18, 2009, 4:13pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/9 "2009-07-18T16:13:31Z")
**ecg** covered the range of OSes in space equipment, so I won’t repeat his tale. Oh and he scooped me on the ATM answer too! [This](http://en.wikipedia.org/wiki/Apollo_Guidance_Computer) is a link to the wiki page about the Apollo Guidance Computer. Considering it was built so long ago, I was surprised that it included a tiny OS (just a job scheduler really). It was odd to me because I used to work on modems in the early '90’s. We didn’t even use an OS then – just assembly language and interrupts. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [July 18, 2009, 4:21pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/10 "2009-07-18T16:21:58Z")
There are some computers on the space station that use Windows 2000 and XP. They’re very picky about what they install on them. ---
**Author:** ![AndrewJRichards](https://avatars.discourse-cdn.com/v4/letter/a/7ea924/32.png) [@AndrewJRichards](https://boards.straightdope.com/u/AndrewJRichards)\ **Post date:** [July 18, 2009, 6:26pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/11 "2009-07-18T18:26:58Z")
I’ve had this question on my mind for months, and when I was watching some live NASA TV of what’s going on inside the ISS (yeah, that’s what I do with my time), I saw Microsoft Windows on a laptop, took a [screenshot](http://img139.yfrog.com/img139/1852/060208thespacestationus.jpg), and assumed that’s what they use. ---
**Author:** ![emarkp](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@emarkp](https://boards.straightdope.com/u/emarkp)\ **Post date:** [July 18, 2009, 6:33pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/12 "2009-07-18T18:33:38Z")
Windows is used on laptops for non-mission-critical tasks. One of the problems in using computers up in space is that there’s no atmosphere absorbing cosmic rays, so if the chips are too small, a stray cosmic ray can change the output to a computation. Not a big deal for a spreadsheet, but a big deal for a guidance system. So the computer that drives the shuttle is made of 70’s hardware which is hardened against radiation. A great story about the [team that writes the software for the shuttle is here.](http://www.fastcompany.com/magazine/06/writestuff.html) I imagine the ISS has similar concerns. ---
**Author:** ![Chimera](https://avatars.discourse-cdn.com/v4/letter/c/8e8cbc/32.png) [@Chimera](https://boards.straightdope.com/u/Chimera)\ **Post date:** [July 18, 2009, 6:45pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/13 "2009-07-18T18:45:27Z")
To paraphrase what I said in another thread; Picard: _Fire!_ Worf: One moment, Captain. Our Environmental Controls screen keeps popping up over the top of the weapons screen. Riker: Who lets Microsoft write starship software? ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [July 18, 2009, 7:36pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/14 "2009-07-18T19:36:44Z")
> [@Chimera](#): > > To paraphrase what I said in another thread; > > Picard: _Fire!_ > Worf: One moment, Captain. Our Environmental Controls screen keeps popping up over the top of the weapons screen. > Riker: Who lets Microsoft write starship software? Well, they shouldn’t have let Wesley Crusher install ‘EnviroCon.exe’ as a startup app for the tactical workstation, should they? That was the problem. 😃 (Yes, Starfleet Command has submitted a help ticket about the EnviroCon popover issue, and MS has confirmed that it’ll be resolved with the next service pack. Apparently it only happens when WeaponsFire.exe has finished going through the targeting dialog box and the ‘Big Red Button’ is visible.) 🙂 ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [July 18, 2009, 10:42pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/15 "2009-07-18T22:42:19Z")
> [@CaveMike](#): > > This isn’t as true today as it used to be. Windows XP Embedded shows up in a lot of unexpected places. I believe it has a strong presence in ATMs as well as gaming (gambling) machines. > > Occassionally pictures show up of Windows Blue Screen on embedded devices like ATMs. Probably by now these is a whole site dedicated to these type of pics. there is a famous picture of the blue screen of death on the roof of the olymic statium during the Chinese opening ceremonies. One of the actors that was suspended on a cable and running horizontally around the roof is visible in the picture. Our Linux sysadmins have in on the wall to tweek the PC admin. 🙂 ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [July 18, 2009, 10:57pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/16 "2009-07-18T22:57:48Z")
> [@rbroome](#): > > there is a famous picture of the blue screen of death on the roof of the olymic statium during the Chinese opening ceremonies. One of the actors that was suspended on a cable and running horizontally around the roof is visible in the picture. Our Linux sysadmins have in on the wall to tweek the PC admin. 🙂 > **[Blue Screen of Death Strikes Bird's Nest During Opening Ceremonies Torch...](https://gizmodo.com/blue-screen-of-death-strikes-birds-nest-during-opening-5035456)** > > Well, this is just perfect. At the exact moment Li Ning was rounding the lip of the Bird's Nest during the amazing torch-lighting climax, someone snapped > **[Windows Crashes During Olympic Ceremony](https://www.tomshardware.com/news/Windows-Olympics-BSOD,6105.html)** > > Microsoft Windows never lets us down when it comes to BSOD amusement and at the 2008 Summer Olympic Opening Ceremonies it strikes againWith 70 million viewers watching, a record for non-U.S. Olympic Summer Games viewership, how many people do you... ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [July 19, 2009, 10:10am UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/17 "2009-07-19T10:10:29Z")
It’s worth noting that the Space Shuttle systems run on 1 MB of RAM. The code, written in HAL/S, is simple and compact for reliability. The ISS systems are written in [Ada](http://www.seas.gwu.edu/~mfeldman/ada-project-summary.html) and run on [80386SX/80387](http://www.dansdata.com/spacecomp.htm) processors which I don’t think would even run Windows 95. ---
**Author:** ![ChrisBooth12](https://avatars.discourse-cdn.com/v4/letter/c/e95f7d/32.png) [@ChrisBooth12](https://boards.straightdope.com/u/ChrisBooth12)\ **Post date:** [July 19, 2009, 10:19am UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/18 "2009-07-19T10:19:11Z")
I seem to remember hearing a store about a virus getting on the ISS computer systems which would make me think that at least part of their system runes on windows. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [July 19, 2009, 11:37am UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/19 "2009-07-19T11:37:30Z")
> [@ilovetoberandom](#): > > Also, is Cecil right in stating that no “life-or-death” system has been built around Microsoft Windows? Banks? Hospitals? The military? We have critical city services built on Windows Server systems. These are systems that support emergency first responders like e-911 and such, so they could be called life or death systems. The easiest way to address the flakiness or other shortcoming of any system or service is to have several instances of it running simultaneously in different geographic locations. This is known in the IT industry as a High Availability environment. Not only does the HA design address the potential flaws of an OS, but those of the hardware, network connections and other dependencies as well - none of which can ever be made completely immune to bug or breakdown. It seems as though designing for redundancy is less expensive than designing for perfection. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [July 19, 2009, 5:49pm UTC](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440/20 "2009-07-19T17:49:25Z")
> [@Fubaya](#): > > It’s worth noting that the Space Shuttle systems run on 1 MB of RAM. The code, written in **HAL** /S, is simple and compact for reliability. Was somebody’s tongue in their cheek when they named or selected that designation? “If it’s HAL, it’s \*got \* to be good!” [Next page](https://boards.straightdope.com/t/what-operating-system-does-the-space-station-use/503440.md?page=2)