What are space probes?

A space probe is an unmanned spacecraft that flies into outer space. It may land on the Moon or other planets, go into orbit around them, or fly past them. Its purpose is to conduct research: It contains cameras and other advanced equipment so that it can send pictures back to Earth by radio. The first successful space probe took place in 1959 with the Soviet Luna 1, which passed within 3,725 miles (5,995 kilometers) of the Moon's surface after 83 hours of flight. It then went into orbit around the Sun, between the orbits of Earth and Mars. In 1977, the United States launched Voyager 1 and Voyager 2 from rockets. These space probes explored all the giant planets of our outer solar system: Jupiter, Saturn, Uranus, and Neptune; 48 of their moons; and the unique system of rings and magnetic fields for each of those planets.

More recent space probes include Cassini (launched in 1997; currently studying Saturn); 2001 Mars Odyssey (launched in 2001; currently studying Mars); New Horizons (launched in 2006; will begin studying Pluto in 2015); Dawn (launched in 2007 (studied the asteroid Vesta until 2012 and will begin studying the dwarf planet Ceres in 2015); and Juno (launched in 2011; will begin studying Jupiter in 2016).