An extrasolar planet discovered around one of the brightest stars in the sky would be a prime target for follow-on observing and characterization, especially if the planet were within the star's habitable-zone. The brightest stars are, however, often not considered to be practical targets for photometric planetary transit searches, despite the scientific rewards that finding a planet around these stars would provide. Exo-PlanetSat is a proposed satellite constellation that will survey the brightest G- and K-dwarfs across the entire sky and look for transits of Earth-sized planets in the habitable-zone. By using measurements of stellar orientations provided primarily by asteroseismic observations, only those stars whose axes lie near 900 to our line of sight will be observed. This increases the transit probability of a habitable-zone planet from 0.5% to 5%, lowering the number of stars that need to be examined by a factor of ten. This in turn enables the design of a practical survey of the brightest stars. A proposed concept of operations envisions thirty small spacecraft in low Earth-orbit, each individually targeted onto a bright star. Over the course of four years, these spacecraft will able to observe a sufficient number of solar-like stars to expect the detection of three habitable-zone Earths with high statistical confidence, assuming that every star has such a planet in orbit.

The past decade has delivered remarkable discoveries in the study of exoplanets. Hand-in-hand with these advances, a theoretical understanding of the myriad of processes that dictate the formation and evolution of planets has matured, spurred on by the avalanche of unexpected discoveries. Appreciation of the factors that make a planet hospitable to life has grown in sophistication, as has understanding of the context for biosignatures, the remotely detectable aspects of a planet's atmosphere or surface that reveal the presence of life. Exoplanet Science Strategy highlights strategic priorities for large, coordinated efforts that will support the scientific goals of the broad exoplanet science community. This report outlines a strategic plan that will answer lingering questions through a combination of large, ambitious community-supported efforts and support for diverse, creative, community-driven investigator research.

For the first time in human history, we know for certain the existence of planets around other stars. Now the fastest-growing field in space science, the time is right for this fundamental source book on the topic which will lay the foundation for its continued growth. Exoplanets serves as both an introduction for the non-specialist and a foundation for the techniques and equations used in exoplanet observation by those dedicated to the field.

A complete and in-depth review of exoplanet research, covering the discovery methods, physics and theoretical background.

The challenge of communication in planetary exploration has been unusual. The guidance and control of spacecraft depend on reliable communication. Scientific data returned to earth are irreplaceable, or replaceable only at the cost of another mission. In deep space, communications propagation is good, relative to terrestrial communications, and there is an opportunity to press toward the mathematical limit of microwave communication. Yet the limits must be approached warily, with reliability as well as channel capacity in mind. Further, the effects of small changes in the earth's atmosphere and the interplanetary plasma have small but important effects on propagation time and hence on the measurement of distance. Advances are almost incredible. Communication capability measured in 18 bits per second at a given range rose by a factor of 10 in the 19 years from Explorer I of 1958 to Voyager of 1977. This improvement was attained through ingenious design based on the sort of penetrating analysis set forth in this book by engineers who took part in a highly detailed and amazingly successful pro gram. Careful observation and analysis have told us much about limitations on the accurate measurement of distance. It is not easy to get busy people to tell others clearly and in detail how they have solved important problems. Joseph H. Yuen and the other contribu tors to this book are to be commended for the time and care they have devoted to explicating one vital aspect of a great adventure of mankind.