https://www.csmonitor.com/Science/Spacebound/2017/0428/To-colonize-space-start-closer-to-Earth?cmpid=ema:nws:Science%2520Weekly%2520%2808/17/2017%29&utm_source=Sailthru&utm_medium=email&utm_campaign=ScienceNewsletter%20081717&utm_term=Science_final