With the commas separating born and raised on Mars from the rest of the sentence, those words could be left out without changing the essential meaning of the sentence. Since it’s clear that where this man is from is important to what’s going on, however, you can’t leave out that part.
I got rid of the and before focuses because it was making the sentence a bit clunky. Then I added a comma after sky because the actions are in a sort of list: looks, focuses, and dreams.
Get rid of the em-dash after dreams and begin a new sentence. If you want a dramatic pause for some reason, use an ellipsis, not an em-dash. (Actually, I’ve just decided that I do want a pause after dreams, so that’s what I’ll do.)
A man born and raised on Mars looks up at the Martian sky, focuses on a pale blue dot, and dreams… He is far too poor to afford a trip to Earth.