Our Solar System at a Glance. Information Summaries.

The United States has explored the solar system with automated spacecraft and human-crewed expeditions that have produced a quantum leap in our knowledge and understanding of the solar system. Through the electronic sight and other "senses" of our automated spacecraft, color and complexion have been given to worlds that for centuries appeared to eyes on Earth as fuzzy disks or indistinct points of light and dozens of previously unknown objects have been discovered. Following a categorical listing of 41 NASA unmanned spacecraft launched between 1959 to 1990, this NASA publication contains numerous photographs and presents factual summaries of the following: (1) the evolution of automated spacecraft; (2) current knowledge about the Sun including information on spacecraft that visited the Sun and future solar missions; (3) conditions on Mercury, especially information that was learned from the Mariner 10 spacecraft; (4) information on Venus as gleaned from Mariner 2, Mariner 5, the Pioneer Venus Orbiter, the Pioneer Venus Multiprobe, and Magellan spacecraft; (5) information about the Earth as learned from trips into space; (6) information about the moon, the Apollo program, and theories on the origin of the moon; (7) detailed information on Mars including information from spacecraft on its topography, prospects for harboring extraterrestrial life, and its two moons Phobos and Deimos; (8) research on asteroids and the results of meteoroid collisions with the earth; (9) data gathered on Jupiter and its moons Io, Europa, Ganymede and Callisto; (10) data on Saturn and its rings; (11) information on Uranus, its numerous icy moons including Miranda, Ariel, Umbriel, and Titania; (12) information on Neptune and its moons including Proteus and Nereid; (13) data concerning Pluto our most distant planet and its one moon Charon; and (14) information on the composition and orbits of comets including Halley's comet. A pictorial summary chart gives further information on the planets including mean distance from the sun, relative size, periods of revolution and rotation, inclination, eccentricity, and composition of their atmospheres. (PR)