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James Webb Telescope will run a proprietary JS interpreter by a bankrupt company

154 points by etrevino 8y ago

redleggedfrog 7y ago
I think you have to look at the reality of the situation. The last 10 years have created a legion of developers who are really only familiar with JavaScript. They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. But in reality, that's fine. They'll muddle through on something like this, finally getting it to work through endless tinkering, and it'll be fine. Remember, the entire internet now pretty much runs on this premise. And it's fine, right?
- joekrill 7y ago
  So what exactly makes a "proper programming language"?
  - apta 7y ago
    Not JavaScript
  - amluto 7y ago
    In the context of a critical, long-running, resource-constrained system, a language + runtime that can have deterministic memory usage. So: not JavaScript and probably not J2SE either.
  - NotAnEconomist 7y ago
    Having written in it for a while, JavaScript just kind of is "meh". TypeScript, for instance, is a much better development experience in terms of language constructs, but that only makes the package management situation stand out more.
  - redleggedfrog 7y ago
    I could see how that would be considered inflammatory, but it was not intended that way. I have a somewhat fuzzy definition. "A programming language that has more 'intent' to it." For example, Rust. The designers had definite ideas about what they were creating, noted the trade-offs, and implemented features based on those decisions. You can say that about lots of languages - Java, C#, Swift, or if you need to go back 10 years, Java <g />, C, or maybe even Python. JavaScript on the other hand was cobbled together in a few weeks by some poor fellow who was under impossible deadlines. And it shows. We've all seen the "Wat" video. Programming in JavaScript is a minefield of bizarre phenomena. Function scopes as namespaces. Nutty math. It succeeds in spite of itself because, a. It's rarely used for anything truly important, and b. It runs on the most popular run-time environment on the planet. Not that you can't do great things with JavaScript. But just about any other language would have been preferable.
    - moron4hire 7y ago
      Most of the "wat" video's complaints also apply to Python. And JavaScript has had many more years of considered design and development than when JQuery or Node made it popular.
      - orf 7y ago
        They really don't.
      - londt8 7y ago
        You are thinking of something else than python? Python has strong, dynamic type system with little implicit type conversions.
      - deathanatos 7y ago
        > Most of the "wat" video's complaints also apply to Python. No, they don't. All of Wat's complaints against JS, in order of presentation: > [] + [] ; JS: '', Python: [] Python uses + between arrays for concatenation, just like strings, which I think is reasonable. JavaScript does random crap. > [] + {} ; JS: '[object Object]' (that's a string, not an object), Python: TypeError. Again, Python's output here is reasonable, JS's is off the deep-end. > {} + [] ; JS: 0 (the integer) Python: TypeError Again, Python's output here is reasonable. JS appears to demonstrate that + isn't commutative, but that's too rosy a picture: in this case, + actually is commutative, as ({} + []) and ([] + {}) are the same string, but without the parentheses we get 0. Yes, the lack of parentheses changes the value JS emits.¹ > {} + {} ; in Wat: NaN, in Chrome/Node: '[object Object][object Object]', in Python: TypeError Similar to before, Python errors out on the garbage, JS just keep computing ever more insane values. > [longer example, but boils down to "wat"+1 doing something and "wat"-1 doing something else for comedic effect. Python TypeErrors on both of these. Python certainly has its own warts, but they are not as ridiculous as the warts that JS carries around. ¹AIUI, {} + [] is parsed as empty code block, implicit semicolon, unary plus, empty array. The parentheses force the grammar to evaluate the entire thing as an expression, so ({} + []) parses instead as a parenthesized empty object, binary plus, empty array.
  - bobcostas55 7y ago
    It's one where empty array plus empty array does _not_ equal an empty string.
  - Avshalom 7y ago
    integers.
  - maxerickson 7y ago
    Cashew nuts!
- jvanderbot 7y ago
  It's classic s/w. Over budget, under spec'd, and arbitrarily the language of the internet.
  - mtberatwork 7y ago
    > and arbitrarily the language of the internet. I think you mean the Web.
- zaarn 7y ago
  > The last 10 years have created a legion of developers who are really only familiar with JavaScript That probably played 0 role into this. When the project was created, about 20 to 15 years ago, people put in the design specs. The language selection was JS, Python 1.5 (1.5, not 2, not 3, 1.5, released in 1999) and a custom script language. NASA decided for JS because Python used more memory. The JS that is being run is essentially IE6 or IE5-level, so none of the modern features introduced in IE8 and forwards that make it all so easy. I'd expect more modern variants of JS (TypeScript) or even something like Rust to make an appearence in 15 years or so. Atleast for these kinds of missions.
  - plopz 7y ago
    Yeah, in 2003 this version of js worked with vxworks and didn't leak memory like python. I'm sort of surprised they didn't go with tcl though.
    - harshreality 7y ago
      The reason they didn't choose tcl had nothing to do with the language. > 2. An attempt was made to port each scripting engine to the VxWorks real-time operating system on a flight-like Power PC by embedding it into a payload flight software application. TCL was dropped from the study when it could not be successfully ported to VxWorks. JavaScript, Python and G-script were successfully ported and a series of tests with prototype flight software applications were run in order to rank them against the success criteria. https://www.scribd.com/document/407354589/Event-driven-James-Webb-Space-Telescope-operations-using-on-board-JavaScripts https://www.scribd.com/document/407354589/Event-driven-James...
      - plopz 7y ago
        Ahh, that makes sense then.
      - cartoonfoxes 7y ago
        I would have assumed porting TCL would have been the most straightforward of the bunch. What features made it so difficult to work with?
- nepeckman 7y ago
  This language choice was made 10 years ago by developers working for NASA. While I think it was a questionable choice, I don't think it was a hype driven choice and I don't think its accurate to say these developers only know JavaScript.
  - mturmon 7y ago
    Come to think of it, STScI, which is where those developers worked (and maybe still do), was always a favorable environment for Python. Back in the early 2000s, before Numpy was a thing, STScI developed an image-file-reader for Python called PyFITS, and an underlying array extension to Python that allowed multiple base types, slicing, etc., called numarray (e.g., see https://scipy.github.io/old-wiki/pages/History_of_SciPy.html https://scipy.github.io/old-wiki/pages/History_of_SciPy.html). In some sense, STScI might have been expected to prefer Python to JS.
- wayneftw 7y ago
  > They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. I've done C, C++, C#, Java, Basic and Python for a living in the past and I always make rock solid software. JavaScript is by far the most productive programming language that I've used to do this. People who think there's such a thing as an objectively "proper" programming language that they haven't even named are actually the problem with this industry, not JavaScript developers.
  - lallysingh 7y ago
    > I always make rock solid software Everything else you claim is suspect because you said this.
    - wayneftw 7y ago
      There's really nothing but an opinion in my response (and in the item I'm responding to) and a bit of bragging certainly doesn't invalidate that in the slightest. Besides that, if you think that there are no people out there who can consistently write solid software, well...you're just flat out wrong. (And if you think you can't find them on HN, well wrong again...)
      - citrablue 7y ago
        I think the apparent hubris is what they're referring to, and that it is a negative indicator of developer self-awareness, while humility and willingness to acknowledge past mistakes are positive signs. Honestly, if you've always delivered rock solid software, you're some sort of mythical creature.
        ben_w 7y ago
        There’s a comic, I forget where, that says the difference between good and bad developers is that while both cause the code reviewer to exclaim “WTF?”, the bad developers causes far more of them. :)
- bregma 7y ago
  > Remember, the entire internet now pretty much runs on this premise. And it's fine, right? Oh, great, a space telescope run like the internet. Now every 2-bit remote galaxy out there is going to be making toxic comments about the Earth and human civilization as we know it. Be careful not to mention things like white dwarfs, or you'll be in for it from all sides. Thanks JavaScript. Way to ruin the night sky for all of us.
  - JamesWebb 7y ago
    JWST will orbit earth, they won't know about it in remote galaxies.
    - seniorsassycat 7y ago
      Jwst will orbit the Earth sun l2 Lagrange
  - seeker61 7y ago
    Don't worry a little banner will appear in front of it telling the real truth about 9-11
    - beamatronic 7y ago
      You have viewed 2 of your 5 complimentary images for this month
- ergothus 7y ago
  > They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. I've been coding since I was kid, and professionally for over 20 years. I've used a few different languages, in a few different contexts, but Iv'e done JS in front/backend for the last 7 years or so and I find statements like these utterly tiresome. Sure, there are lots of naive JS devs...but I can say the same for Java, or any other language that is "a proper programming language". A lot of JS code is written to optimize for things that may it not seem like "solid software" - but I've seen a lot of terrible "solid software". When we collectively realize that our industry is so young, that the best practices of yesteryear are often now viewed as mistakes (and that the practices from before that were maybe the right idea...), and that we really DON'T KNOW the correct answer, maybe then we'll stop loving to hate on people who are doing work that we might not do so well at if we tried it. I don't know your intentions in saying what you said, but in general there is a LOT of smug looking-down on web development in general and JS development in particular. Arrogance is not a good look, and derision is worse. The industry has improvements it can make, certainly, but this is something true of us all, not something restricted to one sub-group while everyone else is doing thing The Right Way.
  - eitland 7y ago
    Good coders can be productive and write good code in any mainstream language, contrary to what is said in the famous "PHP: a fractal of bad design"[0]. That said JavaScript has a number of the same problems as PHP and pointing this out should be equally acceptable as pointing out issues with PHP[1], and while I'm impressed that it was created in three weeks and impressed with the JS community we shouldn't pretend it is a very well designed language. People being productive in JS is pretty much a result of an amazing ecosystem, not because of the language. For a very simple example of what JavaScript could have been, look at Typescript: anything you can do in JS you can also do in TS. In fact, "porting" from JS to TS is as simple as changing the file extension. Yet except for the need for transpiling TS is massively easier to work with and can eliminate whole classes of problems when used correctly. Source: Have programmed and maintained others creations in JS and later TS. [0]: https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/ https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/ [1]: I also have programmed my fair share of PHP code. It doesn't have to be bad. But I'll happily admit that it isn't the prettiest or most well designed language I know.
- deleted 7y ago
  [deleted]
- benj111 7y ago
  "They'll muddle through on something like this, finally getting it to work through endless tinkering, and it'll be fine" This is NASA we're talking about. For a satellite. There will be no muddling, or tinkering. Nasa isn't in the market to hire any old web dev you know. This is rocket science. Edit: On second reading you may not be a serious as I first thought :)
- deleted 7y ago
  [deleted]
anuraj 7y ago
Why is it even running JavaScript? That too for mission critical application.
- jvanderbot 7y ago
  The mission critical stuff is not JS. Sequences are encoded as JS.
  - bdamm 7y ago
    What software on the JWST is not mission critical?
    - jvanderbot 7y ago
      Fair point. Sequence scripts are written in js. Execution of sequences, hardware control, resource management, and everything not sequence markup is not. The sequences are not flight software (imho), but the interpreter is.
- JudgeWapner 7y ago
  not defending it, but I think it boils down to the requirement to be able to quickly issue specific commands to various subsystems. So one choice would be a Domain-Specific Language, the other would be an "everyone-already-knows-it" language like JS.
simplicio 7y ago
Is there a better source for this? The link takes me to a reddit page that in turn leads to an apparently deleted tweet
- krisoft 7y ago
  The paper "Event-driven James Webb Space Telescope Operations" (doi: 10.2514/6.2006-5747) seems to confirm the information. Also previous discussion on HN: https://news.ycombinator.com/item?id=13009598 https://news.ycombinator.com/item?id=13009598
ThePhysicist 7y ago
JS is not so uncommon in science, during my PhD I did electron lithography using a scanning electron microscope that you could (well, had to) program with JS. It was built by a German company, I don’t think it’s the same one that built the software for James Webb though.
- leetbulb 7y ago
  That microscope must have used a lot of memory. /s This is good to hear though. JS is a great entry level scripting language and makes sense for applications like this where you just need to get a specific job done rather than worrying about everything else that comes with code being the actual product.
exabrial 7y ago
JavaScript to direct a satellite? Good grief. That's like mowing your lawn with a burst from an A-10. As much as we're spending on this thing, I feel like it could be written in Rust and verified with TLA+.
- jvanderbot 7y ago
  I think comparing js to a highly specialized, well constructed, ruggedized, and well loved machine is a bit off. It's more like mowing your lawn with whatever you can grab from the gas station on the way home. Something surely ubiquitous, familiar, convenient (for you), and completely unsuited given we have tools for it.
  - exabrial 7y ago
    Good point.
kreetx 7y ago
Why not a language that has types, perhaps C or Rust? Even if they use TypeScript then still why not go something more lower level?
- zaarn 7y ago
  TypeScript didn't exist when the decision on the language was made. And nobody will launch anything into space that didn't see a decade of testing and then it still needs to be integrated into a craft that will launch 10 yrs in the future. They wanted a scripting language, likely to make updating stuff around the craft easier, it's high level control so low level languages don't make that much sense. You'll likely see Rust and other modern languages in about 15 years or so flying into space.
  - jvanderbot 7y ago
    C++ finally made it. You're probably right about 2 decades for Rust .... mho.
  - tropo 7y ago
    Jython dates to January 17, 2001. The spacecraft would just have the JVM of course.
- jvanderbot 7y ago
  Sequences are often a markup language, and are (necessarily) interpreted on board.
- hliyan 7y ago
  Somehow I don't think /node_modules will fit.
- Rebelgecko 7y ago
  Rust and Typescript didn't exist when this decision was made. The 2MB size limit would also take some engineering effort to workaround for both of those languages.
- z3t4 7y ago
jvanderbot 7y ago
heres a live link. And paper. Sorry I'm on mobile. FWIW, they are sending observation sequences marked up as some custom JS, and an onboard interpreter will turn those into C&DH sequences and spool them out. That decision seems arbitrary, given most onboard executives use a ... more standardized markup lang for sequences. https://www.google.com/url?q=http://www.stsci.edu/~idash/pub/dashevsky0607rcsgso.pdf&sa=U&ved=2ahUKEwjN-L6F6-jhAhVKslQKHe-LBqkQFjAAegQIBxAB&usg=AOvVaw3MOdhMNkCpks-n5XuFVDG- https://www.google.com/url?q=http://www.stsci.edu/~idash/pub... https://mobile.twitter.com/alteredq/status/800858908851982336?lang=en https://mobile.twitter.com/alteredq/status/80085890885198233...
peatmoss 7y ago
This decision was apparently made some time ago, back when the software landscape looked pretty different. I have to wonder how many decisions we make now with software will live long enough to seem as questionable. If prior longevity is used to predit future longevity it’s an interesting thought exercise to think of how you’d write software. If projected longevity were my concern for a system, I’d almost certainly want things written in C or C++, maybe Ada. If I wanted high level scripting, I’d probably embed a Scheme.
salamanderman 7y ago
At Lockheed in 2004, which had recently lost their bid on James Webb, some of us were trying to tell folks at Nasa about Lua. In all fairness, a lot of satellites are running bizarre, one-off scripting languages created as needed. In the cases I know of, it was usually one junior engineer who made something without any spec. In the end they are always rigorously tested.
- mfatica 7y ago
  is there a Lua implementation for VxWorks? That seems to be the main constraint in their choice of language(s)
  - whatshisface 7y ago
    Lua can be statically linked to anything written in C, because it's just a bunch of C code. That is one of the biggest reasons why it has seen such wide adoption. To quote their readme, >Building Lua should be straightforward because Lua is implemented in pure ANSI C and compiles unmodified in all known platforms that have an ANSI C compiler. [0] http://www.lua.org/manual/5.3/readme.html#install http://www.lua.org/manual/5.3/readme.html#install
  - cptskippy 7y ago
    Yes. Canon's older Powershot series of cameras ran VxWorks, and if you're familiar with CHDK, Lua is one of the supported scripting languages.
- Balgair 7y ago
  Related: In Specialty Engineering, we had to irradiate the hell out of the CPUs and see what happened. This was done by running cables into the rad chambers and then running a program on the CPU to test all of the chips and other stuff on the motherboards as they were blasted. Most of the time, we just went up in dosage until the system failed, which wasn't long. One thing that always stuck out to me though, were the counters in the room. We'd leave one in the test chamber as close to the parts as possible, to get more accurate readings. Those little counters always borked out. The 7-part digital counters would just flicker and dance about in the rads. These 'hardened' counters would always fail first, and a lot sooner, than the CPUs. I was just doing the dosing, not the code in the CPU. But if those very simple counters were fried well before the more complicated CPUs, and they were not in the full thrust of the radiation, then I can't imagine what those guys were doing to mitigate their code in that rad-soup. It was very impressive.
brent_noorda 7y ago
I led the team that created the JavaScript interpreter JWST is using, and I still occasionally work with them on it. 16 (or so) years ago I was blown away at the amount of research NASA did covering all of the control language options, and of course glad that they selected ours. The language itself wasn’t so important as having adequate performance, robustness, memory use, reproducibility and extreme QC.. the way I remember thinking about it was that when your system is running a million miles away, you can’t send an IT tech to press ctl-alt-del when something goes wrong. IMHO they made a well-researched choice that continues to hold up.
- _bxg1 7y ago
  I write JS professionally, and I can't fathom why they would use it on something so important and correctness-critical. Can you shed some light on that? Edit: Thinking about it, I have read that Lisp was used for early NASA missions because of its ability to be rewritten in-place, which JS mostly shares. Still, JS has so many weird quirks and so easily throws exceptions. And it can't be very fast at processing images. Maybe it's only used for high-level control logic?
  - ChristianBundy 7y ago
    > And it can't be very fast at processing images. Why not?
    - _bxg1 7y ago
      Because it's a very a CPU-intensive task? It's all relative, but in 2003 JS was one of the worst languages you could possibly use for that. Of course it's moot if they aren't actually planning to use it for that side of things.
      - semicolon_storm 7y ago
        Speed can vary from interpreter to interpreter. I haven't seen any benchmarks of this interpreter, so we don't know how fast it may be. Maybe their JS interpreter applies some restrictions to the language that greatly speeds it up?
adreamingsoul 7y ago
wow, I’m suprised by all the people wanting to point out the cons with JavaScript. It’s unfortunate and unnessecary.
- hombre_fatal 7y ago
  HNers can't resist their "DAE hate javascript" hobby horse in a topic with javascript in the title. Usually accompanied with the snipe that you only use javascript because you're incompetent and have never tried anything else.
tokai 7y ago
The only thing wrong here is proprietary part.
- Bonooru 7y ago
  Usually with a project of this scale, you'd also get a copy of the source code for the interpreter or a provision in the contract for a copy of the source in the case that the company that wrote the interpreter goes out of business.
tannhaeuser 7y ago
What's a "proprietary" JavaScript interpreter anyway? JavaScript (ECMAScript) is a standardized language with many implementations, and ES3/ES5 is arguably one the most portable languages of all time.
- noselasd 7y ago
  It's just what it says - an implementation of Javascript that is proprietary.
neetdeth 7y ago
Brings to mind this article, a history of the rise and fall of Common Lisp at JPL, which was almost selected as the control language for their robotic space missions. http://www.flownet.com/gat/jpl-lisp.html http://www.flownet.com/gat/jpl-lisp.html And of course, JavaScript having its origins as a more marketable syntactic overhaul of Lisp for in-browser scripting, it's not hard to see how we end up with JS on the JWST for many of the same reasons. Like others, I tend to idealize space tech from a distance and imagine it using technologies that are across the board better, cooler, more pure than anything that stays on the ground. While the need for extreme reliability does change things a lot, it turns out most of the same forces that guide software selection anywhere else are at play there as well.

154 points by etrevino 8y ago

I think you have to look at the reality of the situation. The last 10 years have created a legion of developers who are really only familiar with JavaScript. They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. But in reality, that's fine. They'll muddle through on something like this, finally getting it to work through endless tinkering, and it'll be fine. Remember, the entire internet now pretty much runs on this premise. And it's fine, right?

joekrill 7y ago
So what exactly makes a "proper programming language"?
- apta 7y ago
  Not JavaScript
- amluto 7y ago
  In the context of a critical, long-running, resource-constrained system, a language + runtime that can have deterministic memory usage. So: not JavaScript and probably not J2SE either.
- NotAnEconomist 7y ago
  Having written in it for a while, JavaScript just kind of is "meh". TypeScript, for instance, is a much better development experience in terms of language constructs, but that only makes the package management situation stand out more.
- redleggedfrog 7y ago
  I could see how that would be considered inflammatory, but it was not intended that way. I have a somewhat fuzzy definition. "A programming language that has more 'intent' to it." For example, Rust. The designers had definite ideas about what they were creating, noted the trade-offs, and implemented features based on those decisions. You can say that about lots of languages - Java, C#, Swift, or if you need to go back 10 years, Java <g />, C, or maybe even Python. JavaScript on the other hand was cobbled together in a few weeks by some poor fellow who was under impossible deadlines. And it shows. We've all seen the "Wat" video. Programming in JavaScript is a minefield of bizarre phenomena. Function scopes as namespaces. Nutty math. It succeeds in spite of itself because, a. It's rarely used for anything truly important, and b. It runs on the most popular run-time environment on the planet. Not that you can't do great things with JavaScript. But just about any other language would have been preferable.
  - moron4hire 7y ago
    Most of the "wat" video's complaints also apply to Python. And JavaScript has had many more years of considered design and development than when JQuery or Node made it popular.
    - orf 7y ago
      They really don't.
    - londt8 7y ago
      You are thinking of something else than python? Python has strong, dynamic type system with little implicit type conversions.
    - deathanatos 7y ago
      > Most of the "wat" video's complaints also apply to Python. No, they don't. All of Wat's complaints against JS, in order of presentation: > [] + [] ; JS: '', Python: [] Python uses + between arrays for concatenation, just like strings, which I think is reasonable. JavaScript does random crap. > [] + {} ; JS: '[object Object]' (that's a string, not an object), Python: TypeError. Again, Python's output here is reasonable, JS's is off the deep-end. > {} + [] ; JS: 0 (the integer) Python: TypeError Again, Python's output here is reasonable. JS appears to demonstrate that + isn't commutative, but that's too rosy a picture: in this case, + actually is commutative, as ({} + []) and ([] + {}) are the same string, but without the parentheses we get 0. Yes, the lack of parentheses changes the value JS emits.¹ > {} + {} ; in Wat: NaN, in Chrome/Node: '[object Object][object Object]', in Python: TypeError Similar to before, Python errors out on the garbage, JS just keep computing ever more insane values. > [longer example, but boils down to "wat"+1 doing something and "wat"-1 doing something else for comedic effect. Python TypeErrors on both of these. Python certainly has its own warts, but they are not as ridiculous as the warts that JS carries around. ¹AIUI, {} + [] is parsed as empty code block, implicit semicolon, unary plus, empty array. The parentheses force the grammar to evaluate the entire thing as an expression, so ({} + []) parses instead as a parenthesized empty object, binary plus, empty array.
- bobcostas55 7y ago
  It's one where empty array plus empty array does _not_ equal an empty string.
- Avshalom 7y ago
  integers.
- maxerickson 7y ago
  Cashew nuts!
jvanderbot 7y ago
It's classic s/w. Over budget, under spec'd, and arbitrarily the language of the internet.
- mtberatwork 7y ago
  > and arbitrarily the language of the internet. I think you mean the Web.
zaarn 7y ago
> The last 10 years have created a legion of developers who are really only familiar with JavaScript That probably played 0 role into this. When the project was created, about 20 to 15 years ago, people put in the design specs. The language selection was JS, Python 1.5 (1.5, not 2, not 3, 1.5, released in 1999) and a custom script language. NASA decided for JS because Python used more memory. The JS that is being run is essentially IE6 or IE5-level, so none of the modern features introduced in IE8 and forwards that make it all so easy. I'd expect more modern variants of JS (TypeScript) or even something like Rust to make an appearence in 15 years or so. Atleast for these kinds of missions.
- plopz 7y ago
  Yeah, in 2003 this version of js worked with vxworks and didn't leak memory like python. I'm sort of surprised they didn't go with tcl though.
  - harshreality 7y ago
    The reason they didn't choose tcl had nothing to do with the language. > 2. An attempt was made to port each scripting engine to the VxWorks real-time operating system on a flight-like Power PC by embedding it into a payload flight software application. TCL was dropped from the study when it could not be successfully ported to VxWorks. JavaScript, Python and G-script were successfully ported and a series of tests with prototype flight software applications were run in order to rank them against the success criteria. https://www.scribd.com/document/407354589/Event-driven-James-Webb-Space-Telescope-operations-using-on-board-JavaScripts https://www.scribd.com/document/407354589/Event-driven-James...
    - plopz 7y ago
      Ahh, that makes sense then.
    - cartoonfoxes 7y ago
      I would have assumed porting TCL would have been the most straightforward of the bunch. What features made it so difficult to work with?
nepeckman 7y ago
This language choice was made 10 years ago by developers working for NASA. While I think it was a questionable choice, I don't think it was a hype driven choice and I don't think its accurate to say these developers only know JavaScript.
- mturmon 7y ago
  Come to think of it, STScI, which is where those developers worked (and maybe still do), was always a favorable environment for Python. Back in the early 2000s, before Numpy was a thing, STScI developed an image-file-reader for Python called PyFITS, and an underlying array extension to Python that allowed multiple base types, slicing, etc., called numarray (e.g., see https://scipy.github.io/old-wiki/pages/History_of_SciPy.html https://scipy.github.io/old-wiki/pages/History_of_SciPy.html). In some sense, STScI might have been expected to prefer Python to JS.
wayneftw 7y ago
> They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. I've done C, C++, C#, Java, Basic and Python for a living in the past and I always make rock solid software. JavaScript is by far the most productive programming language that I've used to do this. People who think there's such a thing as an objectively "proper" programming language that they haven't even named are actually the problem with this industry, not JavaScript developers.
- lallysingh 7y ago
  > I always make rock solid software Everything else you claim is suspect because you said this.
  - wayneftw 7y ago
    There's really nothing but an opinion in my response (and in the item I'm responding to) and a bit of bragging certainly doesn't invalidate that in the slightest. Besides that, if you think that there are no people out there who can consistently write solid software, well...you're just flat out wrong. (And if you think you can't find them on HN, well wrong again...)
    - citrablue 7y ago
      I think the apparent hubris is what they're referring to, and that it is a negative indicator of developer self-awareness, while humility and willingness to acknowledge past mistakes are positive signs. Honestly, if you've always delivered rock solid software, you're some sort of mythical creature.
      - ben_w 7y ago
        There’s a comic, I forget where, that says the difference between good and bad developers is that while both cause the code reviewer to exclaim “WTF?”, the bad developers causes far more of them. :)
bregma 7y ago
> Remember, the entire internet now pretty much runs on this premise. And it's fine, right? Oh, great, a space telescope run like the internet. Now every 2-bit remote galaxy out there is going to be making toxic comments about the Earth and human civilization as we know it. Be careful not to mention things like white dwarfs, or you'll be in for it from all sides. Thanks JavaScript. Way to ruin the night sky for all of us.
- JamesWebb 7y ago
  JWST will orbit earth, they won't know about it in remote galaxies.
  - seniorsassycat 7y ago
    Jwst will orbit the Earth sun l2 Lagrange
- seeker61 7y ago
  Don't worry a little banner will appear in front of it telling the real truth about 9-11
  - beamatronic 7y ago
    You have viewed 2 of your 5 complimentary images for this month
ergothus 7y ago
> They have never used a proper programming language and have either never learned or have forgotten what it takes to make solid software. I've been coding since I was kid, and professionally for over 20 years. I've used a few different languages, in a few different contexts, but Iv'e done JS in front/backend for the last 7 years or so and I find statements like these utterly tiresome. Sure, there are lots of naive JS devs...but I can say the same for Java, or any other language that is "a proper programming language". A lot of JS code is written to optimize for things that may it not seem like "solid software" - but I've seen a lot of terrible "solid software". When we collectively realize that our industry is so young, that the best practices of yesteryear are often now viewed as mistakes (and that the practices from before that were maybe the right idea...), and that we really DON'T KNOW the correct answer, maybe then we'll stop loving to hate on people who are doing work that we might not do so well at if we tried it. I don't know your intentions in saying what you said, but in general there is a LOT of smug looking-down on web development in general and JS development in particular. Arrogance is not a good look, and derision is worse. The industry has improvements it can make, certainly, but this is something true of us all, not something restricted to one sub-group while everyone else is doing thing The Right Way.
- eitland 7y ago
  Good coders can be productive and write good code in any mainstream language, contrary to what is said in the famous "PHP: a fractal of bad design"[0]. That said JavaScript has a number of the same problems as PHP and pointing this out should be equally acceptable as pointing out issues with PHP[1], and while I'm impressed that it was created in three weeks and impressed with the JS community we shouldn't pretend it is a very well designed language. People being productive in JS is pretty much a result of an amazing ecosystem, not because of the language. For a very simple example of what JavaScript could have been, look at Typescript: anything you can do in JS you can also do in TS. In fact, "porting" from JS to TS is as simple as changing the file extension. Yet except for the need for transpiling TS is massively easier to work with and can eliminate whole classes of problems when used correctly. Source: Have programmed and maintained others creations in JS and later TS. [0]: https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/ https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/ [1]: I also have programmed my fair share of PHP code. It doesn't have to be bad. But I'll happily admit that it isn't the prettiest or most well designed language I know.
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benj111 7y ago
"They'll muddle through on something like this, finally getting it to work through endless tinkering, and it'll be fine" This is NASA we're talking about. For a satellite. There will be no muddling, or tinkering. Nasa isn't in the market to hire any old web dev you know. This is rocket science. Edit: On second reading you may not be a serious as I first thought :)
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anuraj 7y ago

Why is it even running JavaScript? That too for mission critical application.

jvanderbot 7y ago
The mission critical stuff is not JS. Sequences are encoded as JS.
- bdamm 7y ago
  What software on the JWST is not mission critical?
  - jvanderbot 7y ago
    Fair point. Sequence scripts are written in js. Execution of sequences, hardware control, resource management, and everything not sequence markup is not. The sequences are not flight software (imho), but the interpreter is.
JudgeWapner 7y ago
not defending it, but I think it boils down to the requirement to be able to quickly issue specific commands to various subsystems. So one choice would be a Domain-Specific Language, the other would be an "everyone-already-knows-it" language like JS.

simplicio 7y ago

Is there a better source for this? The link takes me to a reddit page that in turn leads to an apparently deleted tweet

krisoft 7y ago
The paper "Event-driven James Webb Space Telescope Operations" (doi: 10.2514/6.2006-5747) seems to confirm the information. Also previous discussion on HN: https://news.ycombinator.com/item?id=13009598 https://news.ycombinator.com/item?id=13009598

ThePhysicist 7y ago

JS is not so uncommon in science, during my PhD I did electron lithography using a scanning electron microscope that you could (well, had to) program with JS. It was built by a German company, I don’t think it’s the same one that built the software for James Webb though.

leetbulb 7y ago
That microscope must have used a lot of memory. /s This is good to hear though. JS is a great entry level scripting language and makes sense for applications like this where you just need to get a specific job done rather than worrying about everything else that comes with code being the actual product.

exabrial 7y ago

JavaScript to direct a satellite? Good grief. That's like mowing your lawn with a burst from an A-10. As much as we're spending on this thing, I feel like it could be written in Rust and verified with TLA+.

jvanderbot 7y ago
I think comparing js to a highly specialized, well constructed, ruggedized, and well loved machine is a bit off. It's more like mowing your lawn with whatever you can grab from the gas station on the way home. Something surely ubiquitous, familiar, convenient (for you), and completely unsuited given we have tools for it.
- exabrial 7y ago
  Good point.

kreetx 7y ago

Why not a language that has types, perhaps C or Rust? Even if they use TypeScript then still why not go something more lower level?

zaarn 7y ago
TypeScript didn't exist when the decision on the language was made. And nobody will launch anything into space that didn't see a decade of testing and then it still needs to be integrated into a craft that will launch 10 yrs in the future. They wanted a scripting language, likely to make updating stuff around the craft easier, it's high level control so low level languages don't make that much sense. You'll likely see Rust and other modern languages in about 15 years or so flying into space.
- jvanderbot 7y ago
  C++ finally made it. You're probably right about 2 decades for Rust .... mho.
- tropo 7y ago
  Jython dates to January 17, 2001. The spacecraft would just have the JVM of course.
jvanderbot 7y ago
Sequences are often a markup language, and are (necessarily) interpreted on board.
hliyan 7y ago
Somehow I don't think /node_modules will fit.
Rebelgecko 7y ago
Rust and Typescript didn't exist when this decision was made. The 2MB size limit would also take some engineering effort to workaround for both of those languages.
z3t4 7y ago

jvanderbot 7y ago

heres a live link. And paper. Sorry I'm on mobile. FWIW, they are sending observation sequences marked up as some custom JS, and an onboard interpreter will turn those into C&DH sequences and spool them out. That decision seems arbitrary, given most onboard executives use a ... more standardized markup lang for sequences. https://www.google.com/url?q=http://www.stsci.edu/~idash/pub/dashevsky0607rcsgso.pdf&sa=U&ved=2ahUKEwjN-L6F6-jhAhVKslQKHe-LBqkQFjAAegQIBxAB&usg=AOvVaw3MOdhMNkCpks-n5XuFVDG- https://www.google.com/url?q=http://www.stsci.edu/~idash/pub... https://mobile.twitter.com/alteredq/status/800858908851982336?lang=en https://mobile.twitter.com/alteredq/status/80085890885198233...

peatmoss 7y ago

This decision was apparently made some time ago, back when the software landscape looked pretty different. I have to wonder how many decisions we make now with software will live long enough to seem as questionable. If prior longevity is used to predit future longevity it’s an interesting thought exercise to think of how you’d write software. If projected longevity were my concern for a system, I’d almost certainly want things written in C or C++, maybe Ada. If I wanted high level scripting, I’d probably embed a Scheme.

salamanderman 7y ago

At Lockheed in 2004, which had recently lost their bid on James Webb, some of us were trying to tell folks at Nasa about Lua. In all fairness, a lot of satellites are running bizarre, one-off scripting languages created as needed. In the cases I know of, it was usually one junior engineer who made something without any spec. In the end they are always rigorously tested.

mfatica 7y ago
is there a Lua implementation for VxWorks? That seems to be the main constraint in their choice of language(s)
- whatshisface 7y ago
  Lua can be statically linked to anything written in C, because it's just a bunch of C code. That is one of the biggest reasons why it has seen such wide adoption. To quote their readme, >Building Lua should be straightforward because Lua is implemented in pure ANSI C and compiles unmodified in all known platforms that have an ANSI C compiler. [0] http://www.lua.org/manual/5.3/readme.html#install http://www.lua.org/manual/5.3/readme.html#install
- cptskippy 7y ago
  Yes. Canon's older Powershot series of cameras ran VxWorks, and if you're familiar with CHDK, Lua is one of the supported scripting languages.
Balgair 7y ago
Related: In Specialty Engineering, we had to irradiate the hell out of the CPUs and see what happened. This was done by running cables into the rad chambers and then running a program on the CPU to test all of the chips and other stuff on the motherboards as they were blasted. Most of the time, we just went up in dosage until the system failed, which wasn't long. One thing that always stuck out to me though, were the counters in the room. We'd leave one in the test chamber as close to the parts as possible, to get more accurate readings. Those little counters always borked out. The 7-part digital counters would just flicker and dance about in the rads. These 'hardened' counters would always fail first, and a lot sooner, than the CPUs. I was just doing the dosing, not the code in the CPU. But if those very simple counters were fried well before the more complicated CPUs, and they were not in the full thrust of the radiation, then I can't imagine what those guys were doing to mitigate their code in that rad-soup. It was very impressive.

brent_noorda 7y ago

I led the team that created the JavaScript interpreter JWST is using, and I still occasionally work with them on it. 16 (or so) years ago I was blown away at the amount of research NASA did covering all of the control language options, and of course glad that they selected ours. The language itself wasn’t so important as having adequate performance, robustness, memory use, reproducibility and extreme QC.. the way I remember thinking about it was that when your system is running a million miles away, you can’t send an IT tech to press ctl-alt-del when something goes wrong. IMHO they made a well-researched choice that continues to hold up.

_bxg1 7y ago
I write JS professionally, and I can't fathom why they would use it on something so important and correctness-critical. Can you shed some light on that? Edit: Thinking about it, I have read that Lisp was used for early NASA missions because of its ability to be rewritten in-place, which JS mostly shares. Still, JS has so many weird quirks and so easily throws exceptions. And it can't be very fast at processing images. Maybe it's only used for high-level control logic?
- ChristianBundy 7y ago
  > And it can't be very fast at processing images. Why not?
  - _bxg1 7y ago
    Because it's a very a CPU-intensive task? It's all relative, but in 2003 JS was one of the worst languages you could possibly use for that. Of course it's moot if they aren't actually planning to use it for that side of things.
    - semicolon_storm 7y ago
      Speed can vary from interpreter to interpreter. I haven't seen any benchmarks of this interpreter, so we don't know how fast it may be. Maybe their JS interpreter applies some restrictions to the language that greatly speeds it up?

adreamingsoul 7y ago

wow, I’m suprised by all the people wanting to point out the cons with JavaScript. It’s unfortunate and unnessecary.

hombre_fatal 7y ago
HNers can't resist their "DAE hate javascript" hobby horse in a topic with javascript in the title. Usually accompanied with the snipe that you only use javascript because you're incompetent and have never tried anything else.

tokai 7y ago

The only thing wrong here is proprietary part.

Bonooru 7y ago
Usually with a project of this scale, you'd also get a copy of the source code for the interpreter or a provision in the contract for a copy of the source in the case that the company that wrote the interpreter goes out of business.

tannhaeuser 7y ago

What's a "proprietary" JavaScript interpreter anyway? JavaScript (ECMAScript) is a standardized language with many implementations, and ES3/ES5 is arguably one the most portable languages of all time.

noselasd 7y ago
It's just what it says - an implementation of Javascript that is proprietary.

neetdeth 7y ago

Brings to mind this article, a history of the rise and fall of Common Lisp at JPL, which was almost selected as the control language for their robotic space missions. http://www.flownet.com/gat/jpl-lisp.html http://www.flownet.com/gat/jpl-lisp.html And of course, JavaScript having its origins as a more marketable syntactic overhaul of Lisp for in-browser scripting, it's not hard to see how we end up with JS on the JWST for many of the same reasons. Like others, I tend to idealize space tech from a distance and imagine it using technologies that are across the board better, cooler, more pure than anything that stays on the ground. While the need for extreme reliability does change things a lot, it turns out most of the same forces that guide software selection anywhere else are at play there as well.