The idea that humans could become a multi-planetary species is not as far-fetched as you might think. But where would they go? Sending people to Mars is within the grasp of science today, says Leonard David, an award-winning space journalist from Golden, and the author of “MARS: Our Future on the Red Planet.” Amanda Hendrix, senior scientist at the Planetary Science Institute in Niwot, and co-author of “Beyond Earth: Our Path to a New Home in the Planets," says Titan, a moon of Saturn, has an accommodating atmosphere. The duo joined Colorado Matters at the University of Denver, along with aerospace engineer Andrzej Stewart, who lived for a year in a NASA-sponsored Mars simulation habitat in Hawaii.