The Encyclopedia of Space and Astronomy introduces the exciting relationship between modern astronomy and space technology. The book also examines the technical, social, and philosophical influences this important combination of science and technology exerts on our global civilization. With the start of the space age in 1957, scientists gained the ability to place sophisticated observatories in outer space. Since such orbiting astronomical facilities operate above the masking limitations imposed by our planet’s atmosphere, they can collect scientific data in regions of the electromagnetic spectrum previously unavailable to astronomers who could only look at the heavens from the surface of Earth.

Data from orbiting astronomical observatories, as well as from an armada of planetary exploration spacecraft, have completely transformed observational astronomy, astrophysics, and cosmology. Space technology has expanded our view of the universe. Scientists now enjoy meeting the universe face-to-face and harvesting enormous quantities of interesting new scientific data from all the information-rich portions of the electromagnetic spectrum. Some spacecraft are designed to investigate mysterious cosmic rays—those very tiny, but extremely energetic, pieces of galactic and extragalactic material that provide tantalizing clues about extremely violent cosmic processes, such as exploding stars and colliding galaxies. Other spacecraft have explored the solar system.

Through developments in space technology, planetary bodies within the solar system are no longer the unreachable points of wandering light that intrigued ancient stargazers. Today, as a result of flybys, orbital reconnaissance missions, and even landings by a variety of interesting robot spacecraft, these mysterious celestial objects have become familiar worlds. The marvel of space technology has also allowed 12 human beings to walk on the surface of another world (the Moon) and to return safely to Earth with hand-selected collections of rock and soil samples for detailed investigation by fellow scientists.

The major entries and special essays within this book highlight the synthesis of modern astronomy and space technology. This fortuitous union of science and technology has created an explosion in knowledge amounting to the start of a second scientific revolution—similar, but even more consequential, than the first. The first scientific revolution began in the 16th century, when a few bold astronomers used their pioneering observations and mathematics to challenge the long-cherished philosophical position that Earth was the stationary center of the universe.