Elon Musk has long been obsessed with humans going to Mars - populating that dry and inhospitable environment as our first step into a multi-planet existence.
It's a pretty lofty goal and is a big part of why he's pushed SpaceX so hard, trialling rockets and becoming a huge player in the space industry.
Over the last year or two, though, it's fair to say that Musk's public profile has become more focused on other endeavors, in particular his very public purchase of what was then called Twitter.
The social network now known as X clearly takes up a lot of Musk's time and energy, and he's also been going through a pivotal period as the boss of Tesla, too.
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The electric vehicle company has finally launched the Cybertruck in recent months, making good on a quite long-delayed promise to diversify its lineup of cars.
So, that might lead some people to believe that Musk's Mars passion project has taken a backseat compared to other concerns.
While that could be true to some extent, Musk recently took to X to demonstrate that he's still dead set on Mars, responding to a post about one of his starships.
He wrote: "We are mapping out a game plan to get a million people to Mars." Not only that, he gave us a little more detail on just how ambitious he is on this front: "Civilization only passes the single-planet Great Filter when Mars can survive even if Earth supply ships stop coming."
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This shows that he's not just thinking in terms of missions to Mars, but rather in terms of making it a permanent and self-sustaining part of civilization.
The 'Great Filter' he mentioned is a theory that a species can only truly be robust and survive long-term if it has the capability to survive a cataclysmic event, like a meteor hitting its planet or some other apocalyptic event.
This would work for humanity if Mars became an outpost that didn't rely on Earth for its continued survival, as Musk mentions.
Of course, there are immense obstacles to be overcome before we're anywhere near that point - even getting to a place where there's an outpost that does depend on supply ships from Earth isn't exactly imminent.
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Being able to grow and produce food on Mars would be one major step - and while experiments in the International Space Station suggest this is possible in space, it's another thing to do it at scale.
Still, this might put to bed any doubts about Musk's Mars fascination for the time being.