If one reads RFC 1812, one finds that it does not exactly define the term. It uses it in a heading but doesn't use it in a way that agrees with its later definition of "martian", since its explanation of "martian address filtering" encompasses traffic that is not "martian" per its own glossary.
A contemporary definition that is not self-contradictory is in Eric S. Raymond's New Hacker's Dictionary, published four years earlier; but which isn't what RFC 1812 says either, however.
So whilst the people who weren't alive in the 1990s are wrong to be hung up on the "I thought it meant 'from Mars'." confusion, since the saddening reality of 2023 is that we're no nearer to that being a realistic source of confusion than we were in 1991; the obverse of the coin is that, like much of the Jargon File, it's woolly slang set over-hard into stone by Eric S. Raymond and a document from Cisco that it is unwise to rely upon for strict technical meaning.
> So whilst the people who weren't alive in the 1990s are wrong to be hung up on the "I thought it meant 'from Mars'." confusion, since the saddening reality of 2023 is that we're no nearer to that being a realistic source of confusion than we were in 1991;
There’s a Mars Fleet of about 11 operational spacecraft and robotic landers/rovers/etc on or around Mars right now, and in fact the robotic helicopter, Ingenuity, runs Linux. I legitimately thought it was related to those. There were no operational missions at Mars in 1991.
"Runs Linux" is superficial thinking, though. ("Runs Linux" doesn't equate to "uses the Internet Protocol".) There is no more Internet Protocol connectivity to Mars in 2023 than there was in 1991. There is no realistic prospect of this being a possible source of confusion now, in the near future, or possibly ever at the current rate.
Err, NASA/JPL has already been using packet-based networking for communicating to deep space vehicles. Not TCP/IP, it's called "Disruption Tolerant Networking" and it uses a store-and-forward method of packet delivery. I had read about this technique before, and in fact part of my job is in the space industry, hence my confusion. https://www.nasa.gov/home/hqnews/2008/nov/HQ_08-298_Deep_spa...
NASA already sends most data from Mars surface assets to Earth by relaying through Mars satellites (including ESA satellites that NASA provides their Electra radio to), and it's starting to get crowded out there. NASA is gearing up for Mars Sample Return (for which they've already cached samples): https://www.youtube.com/watch?v=t9G36CDLzIg
(And, in fact, Ingenuity, which runs Linux, actually sends its images to the Perseverance rover via radio, which transmits to orbiting Mars satellites, which then transmit to Earth... it's becoming a non-trivial network.)
After that will come crewed missions, maybe starting with orbit (perhaps teleoperating assets on the surface) before surface missions. The number of entities involved on Mars has grown pretty dramatically, with not just NASA, but Europe (ESA), China (rover and orbiter, is planning a sample return mission as well), United Arab Emirates (has an operational satellite right now), India (just concluded their satellite mission about 6 months ago after operating 8 years), and there's starting to be private missions as well, such as Impulse Space and Relativity's 2026 mission and whenever SpaceX gets around to sending Starlink satellites (perhaps for NASA...) or Starship or maybe Lockheed doing the same thing, as they've planned for the Moon ( https://gizmodo.com/lockheed-martin-spinoff-satellite-conste... ).
There's every reason to think there will be more and more need for sophisticated networking technology in deep space, including on Mars.