I don't know about 3 languages, but https://www.fastcompany.com/28121/they-write-right-stuff https://www.fastcompany.com/28121/they-write-right-stuff implies th

I don't know about 3 languages, but https://www.fastcompany.com/28121/they-write-right-stuff https://www.fastcompany.com/28121/they-write-right-stuff implies that there is software written by at least two different groups running on the shuttle. I've also heard anecdotally that some train signalling and on-board control systems run software simultaneously in linuc and freebsd to oessen the chance of simultaneous memory faults. (I didn't get a chance to ask for more details or clarification.)