[nine_k]

I don't think any imports from Mars could be profitable. Except scientific data, of course. The colony will depend on Earth tech for a long time.

The only case for a self-sustained colony I see is some local political extremism. To prefer to live on Mars by one's own means would take some very strong Earth-incompatible views.

[greedo]

The chance of a colony on Mars NOT seeking independence when it reaches a modicum of self-sufficiency is nil. Look at the US; separated by 6-12 weeks of sailing. It's human nature to seek to govern your own affairs, and with travel time to Mars being around 300 days, as soon as they can, they'll become independent.

[reddog]

I don't know. Look at Canada; separated by the same distance yet it remained a colony until 1931.

While rebellious space colonies has been a dependable sci-fi trope since the 50's, I am skeptical things would really work out that way given how dependent Mars would be on Earth for everything other than the very basics of self-sufficiency. I am talking about things like art (music, books, films) and the kinds of developments in science, medicine and engineering that can only be generated by having a support base of 8 billion people.

[Qqqwxs]

I think it also depends on what flag the Mars colony flies. If a country (e.g. the U.S) claims the colony for themselves, I think it makes sense that there will be more and more pressure to disassociate especially as people from different countries on Earth mix together. I can see a united colony, however, something like the ISS, working better as there is the cultural idea of being "for humanity" as opposed to "for this country that not everybody identifies with".

[mkl]

Sports, gameshows etc. that rely on the low gravity seem plausible. Pretty unlikely to sustain an economy, though.

Tourism and some healthcare likewise, but that's not really an import.

[mcv]

The one import from Mars that might be profitable does not come from Mars: resources mined from asteroids. Mars is closer to it (and in a shallower gravity well than Earth), so if for whatever reason we want people closer to asteroid mining operations, that might be a viable niche for Mars.

That's very speculative, though. Asteroid mining is probably going to be entirely robots, and both supply of those robots and the demand for the resources are almost entire based on Earth, so it's very questionable a Mars colony will add any value there. But it's the one area where I can see the possibility.

A refueling station on Deimos, however, sounds like a much more interesting prospect.