SPACE PROBES HAVE VISITED every planet in the solar system. They take photographs and gather data that cannot be collected using Earth-based equipment. Some probes fly past or orbit around planets or moons, while others land. Two Voyager space probes flew past the outer planets in the 1970s and 1980s. Two Viking spacecraft landed on Mars in 1976. The Magellan spacecraft orbited Venus from 1989 and mapped its surface. The Pathfinder spacecraft landed on Mars in 1997 and released a rover vehicle to explore the surface. The Mars Exploration Rover (MER) Mission landed two rovers in 2003. The Cassini space probe reached Saturn in 2004, and in 2005 its mini probe, Huygens, landed on one of its moons, Titan, and became the first probe to land on a moon of
another planet.
