By means of orbiters, landers, rovers and sample return missions, NASA’s revamped campaign to explore Mars, announced today, is poised to unravel the secrets of the red planet’s past environments, the history of its rocks, the many roles of water and, possibly, evidence of past or present life. Six major missions are planned in this decade as part of a scientific tapestry that will weave a tale of new understanding of Earth’s sometimes enigmatic and surprising neighbor.