Potentially science and technology, things that can be transmitted via radio. Maybe Mars could setup a hollywood style entertainment industry :) As far as mine

Potentially science and technology, things that can be transmitted via radio. Maybe Mars could setup a hollywood style entertainment industry :) As far as minerals, I really doubt there are any which would be cheaper to mine on mars, load on a rocket and transport back to earth, than to mine directly on earth. Even if you build a space elevator on Mars (which is much easier than building one on earth). Maybe you could setup a 3 way trade. Even without the space elevator, it's cheaper to ship things from Mars' surface to basically anywhere in the solar system than it is from earth's surface. So Mars could ship oxygen, water, CO2 filters, building materials, maybe even food to an asteroid station (whatever they can't source locally) and the asteroid station could ship whatever they mine from the asteroid to earth.