Overview

On January 2, 1959, the Soviet Union launched Luna 1, the first manmade object designed to explore another celestial body. Luna 1 passed about 3,600 miles above the moon's surface, performing some basic scientific observations before entering a solar orbit. Since then, space probes—primarily American and Soviet/Russian—have explored every major body in the solar system except Pluto. They've landed on the Moon, Mars, and Venus; flown through the erupting dust and gases of Halley's comet; mapped asteroids; and dropped probes into the atmospheres of Jupiter, Venus, and (soon) one of Saturn's moons, Titan. In the latter half of the twentieth century, our vision of the solar system changed from that of small, blurred dots in a telescope to a collection of real, unique planets. As William Burrows...