Timing has always been a key element in my life. I have been blessed to have been in the right place at the right time.

There are a lot of reasons for not doing something. And if humanity had come up with all the reasons for not doing something we wouldn't have spread across the Earth the way we have. There's a curiosity, and I would submit that that curiosity will put human beings on the surface of Mars.

If we go back to the moon, we're guaranteed second, maybe third place because while we are spending all that money, Russia has its eye on Mars. Landing people on the moon will be terribly consuming of resources we don't have. It sounds great - 'Let's go back. This time we're going to stay.' I don't know why you would want to stay on the moon.

Mars has been flown by, orbited, smacked into, radar examined, and rocketed onto, as well as bounced upon, rolled over, shoveled, drilled into, baked and even blasted. Still to come: Mars being stepped on.

Mars has a bit of air pressure; maybe we can build up that atmosphere to be a bit more accommodating to humans.

People communicate in Twittering ways. I've learned how to do that.

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.