The James Webb Space Telescope Is Powered By Javascript

Abdul Ghani

The software used in space travel is sometimes curious. In the case of the JWST, the ISIM is controlled and operated with Javascript. The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) runs on classic Javascript. The scripts used there are classic because it is a Javascript version from 2003.
The ISIM of the JWST during an inspection.Image by NASA/Chris Gunn / CC-BY 2.0 From Flickr

Space computers and their software are always good for a surprise. Because the systems, especially for the more spectacular projects, are in development for many years, often decades, before a start can even be considered. The Verge reports.

And even from the start until the actual use, a lot of time can pass. They like to rely on tried and tested technology; but not without adding a dash of cutting edge - cutting edge early in the project, mind you.

Instrument actions triggered via javascript

So it came about that in the ISIM - these are the instruments attached directly behind the mirror of the JWST - a script processor with a Javascript engine is responsible for commands and telemetry, loading the configuration tables, file operations, and much more. And even if the Script Processor is written in the expected C++: What should really be done is in the Javascript files.

Don't get any hope that this is modern Javascript. The variant used is Scriptease 5.00e, released on January 6, 2003. Even the manufacturer at the time, Nombas, no longer exists. In 2004 the company was bought by Openwave.

Scriptease itself, however, has an interesting background: The whole thing started at Nombas with Cmm, which was a scripting language with C-like syntax. Only later was ECMAScript support built into the product and the software package renamed Scriptease.

But the JWST isn't the only piece of space hardware to have Javascript on it either. SpaceX also uses it in the Crew Dragons touch displays. In a more modern variant.

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Member Of Freelancers Union (USA), Freelance Writer!, and Digital Creator. Ghani Mengal is an enthusiast Freelance blogger and digital marketer. His content has been published and featured on many popular blogs, websites, and publications. Including TeelFeed,, Data-Driven Investor, TextSniper, Scientific Publication The Predict, The Startup, The Ascent, Heart Affairs, Illumination, And The List goes on.


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