For six weeks this summer, a rough uninhabited island in the Arctic Circle became the focus of preparations for a human journey to Mars and a search for life there. Devon Island is within a thousand miles (1,600 kilometers) of the North Pole, just 200 miles (320 kilometers) west of Greenland’s northwest coast and 1,700 miles (2,735 kilometers) north of the U.S.- Canada border. It lies 75 degrees north of the equator, further north than Alaska’s northernmost point.