@EffreyJepstein >they use Linux on the Falcon rockets
I really can't find many details on what they use, but they use claim to use 3 redundant standard AMD64 computers (with no radiation hardening, since it doesn't leave the atmosphere), with the control software written in C++ that "run Linux".

I would guess they're running a cut down version of GNU/Linux, but there's no way to tell.

>I'd imagine whatever realtime performance needed in a satellite is also needed on the rockets
I've read a comment that the rocket engines themselves have POWERPC processors and are controlled by other software, which I'm sure is designed to meet the hard realtime requirements.

I guess the design can handle throttle positions and/or steering commands being delayed by up to ~0.25 seconds, with the right hardware config, you'll usually get much less than that with the realtime patches to Linux as long as the hardware behaves.

I haven't heard of a long-life satellite that uses Linux as its kernel.


>Linux is free software
If it was, the following proprietary software wouldn't be in Linux:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/appletalk/cops_ffdrv.h
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/appletalk/cops_ltdrv.h
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/platforms/8xx/micropatch.c

>all of the userspace systems and offline tooling needed to run a rocket
Yes, it's called GNU.