The ultimate goal of Artemis is to get people to Mars. But there was a time, in the early 1900s, when it was widely believed there was already life there and engineered canals to bring water from the poles to cities. There were skeptics, but it’s hard to overstate how ingrained this idea of Martian life became. Former NPR science correspondent David Baron, of Boulder, has written “The Martians: The True Story of an Alien Craze that Captured Turn-of-the-Century America." He spoke with Ryan Warner last August in front of an audience in Colorado Springs, where some of the story unfolds.