If engineers at this NASA center have their way, the agency’s armada of future Mars spacecraft will seem to arrive at the Red Planet by materializing out of thin air. Their plan involves using the lean and mean Martian atmosphere to brake spacecraft into orbit around Mars. But getting a lander down to a select spot on the fourth planet from the Sun, while avoiding harsh, rough-and-tumble terrain, is an exacting science. For that reason, atmospheric, materials and high-speed specialists at NASA’a Langley Research Center in Hampton, Virginia are revving up their computers and wind tunnels to help shape Mars exploration plans over the next decade and beyond.