While it's the dream of many people to see astronauts on Mars, I don't see it becoming a reality anytime soon. While the solar system is a tiny spot in out galaxy, the gap between Earth and Mars is still very far when you have real humans in the space-craft. I wouldn't be surprised if it took us one or two hundred years to walk on Mars. I don't think humanity will ever colonize the planet either. Humans wouldn't last very long on Mars without a space-suit, so everything would have to built with technology to merely survive. Without a lot of water and food, I could not see a little city on Mars lasting long.
When you do you think astronauts will reach Mars?