How Many Moons Does Saturn Have?

To date, astronomers have discovered 62 moons that orbit Saturn. But, before the Cassini satellite mission that began in 1997, scientists only knew of 18 moons orbiting Saturn. Since then, an additional 44 moons have been discovered. Scientists continue to try and unravel the mysteries that Saturn and the other gas giant planets hold.

Early Moon Discoveries

Prior to man-made satellites being sent into space to take recordings, the only other way to understand celestial bodies was to observe them from Earth through telescopes. For this reason, the planet Saturn was discovered in the 17th Century, only 20 years before some of Saturn’s larger moons were discovered by Giovanni Domenico Cassini.

• Titan was discovered in 1655.
• Lapetus was discovered in 1671.
• Rhea was discovered in 1672.
• Tethys and Dione were discovered in 1684.

After Cassini, it would take another hundred years for William Herschel to discover Mimas and Enceladus in 1789. Another one hundred years would elapse before William Henry Pickering discovered Phoebe in 1898. Finally, another one hundred years would bring the addition of a few more moons, beginning in 1980, still only totaling 18.

Rings Versus Moons Versus Comets

Saturn’s ring system makes it the most recognizable planet in the solar system, next to Earth. All gas giant planets, including Jupiter, Uranus, and Neptune, have these rings, but none show up as brightly as Saturn’s.

The composition of the rings is a bit of a mystery, though they are thought to be composed of water, icebergs and snowballs of various sizes and shapes. However, they are not considered moons, though many of the moons orbit the planet within the ring systems themselves.

The largest of Saturn’s moons are as big or bigger than the Earth’s moon. For this reason, they were easily detected by early astronomers. However, many of Saturn’s smaller moons are no larger than comets.

What separates the moons from comets, though, is their regular orbit around the planet. About half of the moons that orbit Saturn flow in the same direction as the planet itself. This means that the moon satellite was formed as the planet was forming. This is also known as a prograde orbit. The other half of the known moons move in either a prograde or retrograde orbit.

Retrograde orbits are opposite of the planet’s direction. These moons were not created during the formation of the planet but most likely captured by the planet’s gravity as they were floating along. They consist of small planets, and space debris from collisions between celestial bodies.

The Cassini Equinox Mission to Saturn

In 1997, a joint effort between the National Aeronautics and Space Administration (NASA), European Space Agency (ESA), and Italian Space Agency (ASI) launched the Cassini spacecraft. Its mission was to send information to scientists about Saturn and two of its moons, Titan and Enceladus. The satellite reached Saturn on July 1, 2004, and its mission was to be completed in four years. The spacecraft had done such a great job that its mission was extended until September, 2010, costing the country sponsors over $660 billion.