• Now Is the Time to Colonize Mars, Elon Musk Says http://www.nbcnews.com/tech/innovation/now-time-colonize-mars-elon-musk-says-n481906 3 comments 17/12/2015 technology
• Now Is the Time to Colonize Mars, Elon Musk Says http://www.space.com/31388-elon-musk-colonize-mars-now.html? 26 comments 16/12/2015 space