I think it's inevitable that there will be Earthlings establishing a presence on Mars. And I would say that it would certainly take place by 2050 or shortly thereafter.
Buzz AldrinWhen I am getting ready to cross a street, I look both ways before crossing. My bones, my muscles, are not what they used to be, so I am careful when I go up and down stairs, because I've heard stories of older people falling and having very disabling injuries. I have enough things that begin to go a little bit wrong as I get a little bit older.
Buzz AldrinAll the Chinese have to do is fly around the Moon and back, and they'll appear to have won the return to the Moon with humans. They could put one person on the surface of the Moon for one day and he'd be a national hero.
Buzz AldrinAs we begin to have landings on the moon, we can alternate those with vertical launch of similar crew modules on similar launch vehicles for vertical-launch tourism in space, if you want to call it that adventure travel.
Buzz Aldrin