What are you going to find on mars to justify a colony? Best answer I've heard is "a portion of the raw materials you'd need to build a colony", which isn't even a circular justification - it's an incomplete circle!.
Without the added justification of "because it's another planet, and that's so cool", I don't think a mars colony makes a lick of sense.
Mars has a weaker gravity well, so getting to space is a lot easier than it is from Earth. And while the moon might sound better, unlike the Moon, it has enough gravity where the human body might be able to adapt without crippling bone and muscle loss.
This makes Mars pretty ideal as a home base, if you assume that in the future we are planning to mine and process asteroids for rare minerals and metals.
why do we even care about all this. establishing a space station on mars to make it easier to travel the rest of the galaxy.. is already circular logic but we're 100s of years away from achieving that now. 20 to get a human there. 30 more to build anything habitable and then we don't even know if its self sustainable but if it is.. 20 or 30 more to build a viable space center anddddd... we haven't actually improved life at all, just explored a sliver more of the galaxy and none of us will even get to witness it .
Don't forget that "self sustainable" would be a pipe dream - there's no conceivable possibility of producing advanced machinery such as electronics on Mars given current or near-future technology.
Also, there's a very good chance that this type of exploration of Mars will forever contaminate it preventing us from using Mars to explore the origins of biological life, a much more important and achievable goal than space colonization, and one that doesn't shut out the other one in a farther future.
It's a lovely dream though. Lots of people have grown up with that dream - it's going to be hard to give up. Surely we can spend a few bucks on it to show willing and satisfy the dreamers?
Lots of people have grown up dreaming their Hogwarts letter would arrive - I don't think that justifies spending any money to try to build a school of magic.
> establishing a space station on mars to make it easier to travel the rest of the galaxy..
Considering that the "rest of the galaxy", aka the Milky Way is 1,000,000,000,000,000,000 km give or take across, the 250,000,000 km to Mars aren't going to provide much of a head start.
Without the added justification of "because it's another planet, and that's so cool", I don't think a mars colony makes a lick of sense.