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What computer and software is used by the Falcon 9? (2015)

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Re: What computer and software is used by the Falcon 9? (2015)

#11

Post by fsh »

aetherspawn wrote: post #4
jamespetercook wrote: post #2

“They use Chromium and JavaScript for the Dragon 2 flight interface.“ This is the most interesting part for me being a web dev! How likely do you think this is?

Just because they do, doesn’t mean you should. I’m running an automotive firmware project at the moment and there are such things as software integrity levels, and each time you add something to the stack you create quite a large amount of testing and validation and process that needs to be followed. And it’s pretty much impossible to take something existing like Chromium and certify it to what you need. The architec…

I believe the choice of Chromium and JS for the UI simply shows that the astronauts are merely inconvenient payloads. Gagarin's first flight was already fully automated 59 years ago.

Re: What computer and software is used by the Falcon 9? (2015)

#12

Post by ncmncm »

irrational wrote: post #9

I’ve read a bit about how strict the space shuttle coders were. I wonder what they think about the code running this spacecraft. https://www.fastcompany.com/28121/they-write-right-stuff https://history.nasa.gov/computers/Ch4-5.html https://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature...

There are reports that the procedure for fixing bugs on the STS was so heavy-weight that they often redefined non-fatal bugs as correct operation. The example I read of was an error event that dumped thousands of lines of text to the flight console screen, obscuring useful information.

Re: What computer and software is used by the Falcon 9? (2015)

#14

Post by hliyan »

gumby wrote: post #8

Interesting that it’s three identical processors running he same software. I remember just the automated Vienna central train station used a pair of machines, x86 and SPARC, one running the logic in a procedural language (Chill) and the other running in a logic language (Prolog). They didn’t want both processors to share any code, and therefore potentially the same bug.

Looks like the goal is radiation tolerance, not n-version programming.

Re: What computer and software is used by the Falcon 9? (2015)

#15

Post by nullifidian »

Sounds kinda disappointing/irresponsible. Chromium is an overly complex, relatively buggy piece of software. For example I recently experienced a bug where a text I selected was significantly offset from what should have been selected given the pointer position (on linux), a misclicky kind of bug. Considering that the majority of Crew Dragon's controls are through touch screen, maybe even manual docking(not sure, but I don't see a joystick anywhere), my personal experience with chromium does not instill confidence for such critical applications. But I guess they tested it very thoroughly.

C++ and linux do not strike me as mission critical piece of software / language either. My heart desires for something with verified properties, advanced languages with integrated proof checkers, verified OSs, or at least smaller purpose built OSs that were carefully reviewed. But I guess SpaceX is not to blame for this. It's likely such approaches are simply not ready yet. And I know that C++ and linux are common in mission critical applications. JSF avionics is written in C++ for example.

(Not to mention JavaScript in space, in a mission critical role. That shouldn't have happened.)

Re: What computer and software is used by the Falcon 9? (2015)

#17

Post by api »

ncmncm wrote: post #10

Heaven help them if the Javascript they run depends on npm components. When I read about these multiply redundant systems I always want to know what provisions are made for restarting or shutting down a part that is producing wrong answers. Can the Power device reset the machine whose instructions lost the vote? If the two cores disagree, do they both reset? Also, what is done for procedures that must not be interrup…

I highly doubt JS is used outside the UI layer.

Re: What computer and software is used by the Falcon 9? (2015)

#18

Post by api »

jamespetercook wrote: post #2

“They use Chromium and JavaScript for the Dragon 2 flight interface.“ This is the most interesting part for me being a web dev! How likely do you think this is?

That was the most surprising part to me too, but not that surprising. Lots of automotive and newer industrial UIs use Qt Quick with QML which is not all that different from HTML5 and JS with something like React.

It's used in the presentation layer, not the actually control systems.

Re: What computer and software is used by the Falcon 9? (2015)

#19

Post by TomMarius »

api wrote: post #18
jamespetercook wrote: post #2

“They use Chromium and JavaScript for the Dragon 2 flight interface.“ This is the most interesting part for me being a web dev! How likely do you think this is?

That was the most surprising part to me too, but not that surprising. Lots of automotive and newer industrial UIs use Qt Quick with QML which is not all that different from HTML5 and JS with something like React. It's used in the presentation layer, not the actually control systems.

It is very different from the audit/certification viewpoint, and Qt specifically caters to the automotive market

Re: What computer and software is used by the Falcon 9? (2015)

#20

Post by jchw »

nullifidian wrote: post #15

Sounds kinda disappointing/irresponsible. Chromium is an overly complex, relatively buggy piece of software. For example I recently experienced a bug where a text I selected was significantly offset from what should have been selected given the pointer position (on linux), a misclicky kind of bug. Considering that the majority of Crew Dragon's controls are through touch screen, maybe even manual docking(not sure, but…

Once you decide that absolute reliability is unattainable, you can instead aim for sufficient redundancy. It’s not perfect, but with enough safe guards in place it may very well be good enough.
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