On the Cover: A century after Percival Lowell created his iconic drawings of Mars—records of his telescopic observations from atop an Arizona mountain—we know the place better than any other world in the solar system, save for Earth. Many of today’s Mars explorers were inspired by the pioneering work of early astronomers like Lowell and science fiction writers like Edgar Rice Burroughs. The evolution of humankind’s view of the Red Planet is reflected in this 1908 Lowell map overlaid on a global mosaic from Viking 1. Lowell Observatory Archives and NASA/JPL
7 Stepping Lightly to the Stars: Louis Friedmansuggests a practical plan for the next hundred years of spaceflight.