External occulters for direct observation of exoplanets: An overview

Perhaps the most compelling piece of science and exploration now under discussion for future space missions is the direct study of planets circling other stars. Indirect means have established planets as common in the universe but have given us a limited view of their actual characteristics. Direct observation holds the potential to map entire planetary systems, view newly forming planets, find Earth-like planets and perform photometry to search for major surface features. Direct observations will also enable spectroscopy of exoplanets and the search for evidence of simple life in the universe. Recent advances in the design of external occulters - starshades that block the light from the star while passing exoplanet light - have lowered their cost and improved their performance to the point where we can now envision a New Worlds Observer that is both buildable and affordable with today's technology. We will summarize recent studies of such missions and show they provide a very attractive alternative near term mission.