Go to content Go to menu
 


NASA'S SATURN MISSION : THE CASSINI EQUINOX

PictureIn June 2004 , NASA's  Cassini spacecraft entered orbit around Saturn to begin the first in-depth, up-close study of the ringed planet and its domain. As expected, the Saturn System has provided an incredible wealth of opportunities for exploration and discovery. With its initial four-year tour of the Saturn system complete, the spacecraft is conducting an extended mission called the Cassini Equinox Mission.
Cassini's observations of Saturn's largest moon, Titan, have given scientists a glimpse of what Earth might have been like before life evolved. They now believe Titan possesses many parallels to Earth, including lakes, rivers, channels, dunes, rain, snow, clouds, mountains and possibly volcanoes.

The Cassini Equinox Mission is guided by a basic set of science goals that address major scientific questions about the planet, its magnetosphere and rings, Titan and the other icy moons. These objectives are listed in each of the following sections devoted to those topics. Some of the objectives relate to monitoring for seasonal changes in the Saturn System; others are related to new questions spawned by Cassini’s investigations during its first four years at Saturn.
A separate team of scientists plans the observation and measurements for each of the spacecraft's 12 instruments and then analyzes the returned data. Each team is headed by a team leader or a principal investigator. Hundreds scientists from the US, Europe, and across the globe participate in this international mission of exploration and discovery. See Cassini Orbiter Instruments for more.

 

53 moons of Saturn have been officially named. In alphabetic order, they are: Aegaeon, Aegir, Albiorix, PictureAnthe, Atlas, Bebhionn, Bergelmir, Bestla, Calypso, Daphnis, Dione, Enceladus, Epimetheus, Erriapus, Farbauti, Fenrir, Fornjot, Greip, Hati, Helene, Hyperion, Hyrokkin, Iapetus, Ijiraq, Janus, Jarnsaxa, Kari, Kiviuq, Loge, Methone, Mimas, Mundilfari, Narvi, Paaliaq, Pallene, Pan, Pandora, Phoebe, Polydeuces, Prometheus, Rhea, Siarnaq, Skadi, Skoll, Surtur, Suttung, Tarqeq, Tarvos, Telesto, Tethys, Thrym, Titan and Ymir.The moons of Saturn are a diverse collection. Cassini has explored their icy landscapes in unprecedented detail, solving long-standing mysteries and sharing many new surprises: Iapetus has an enormous ridge along its equator in addition to its two sides of remarkably different brightness. Rhea may have its own faint rings. And sponge-looking Hyperion is so porous that impacts tend to just punch into the surface, and its gravity is so low that what material does get ejected tends to leave the moon altogether.

In some ways, the moons Titan and Enceladus have turned out to be the stars of the Cassini mission. Titan, with its thick atmosphere, clouds, and dunes on its surface, plus rivers and lakes of liquid methane, is a rich laboratory for chemistry and processes that may resemble early Earth in a deep freeze. And with its towering south polar plume of icy particles, Enceladus has geologic activity, simple organic compounds and possibly liquid water beneath its frozen Picture
surface, making it incredibly important to the study of potentially habitable environments for life. Both of these moons are tempting targets for future exploration.

Rings

Beautiful, glamorous and mysterious, Saturn's rings are among the most recognizable features in the solar system. They spread over hundreds of thousands of kilometers, yet they are extremely thin – perhaps only 10 meters (about 30 feet) thick. The rings consist of billions of individual particles of mostly water ice which create waves, wakes and other structures.

Named alphabetically in order of their discovery, the order of the main rings outward from Saturn is D, C, B, A, F, G and E. Picture There are also several other faint unnamed rings made up of very fine icy particles.

Scientists still aren't sure exactly how old the rings are. Whether they date back to the early history of the Solar System or formed as recently as the period when the first dinosaurs roamed the Earth is a matter under investigation by Cassini scientists.

Whenever they first formed, it is clear that the rings we observe today were not all created in exactly the same way. For instance, Cassini found that a great plume of icy material blasting from the moon Enceladus and is a major source of material for the expansive E ring. Additionally, Cassini has found that most of the planet's small, inner moons appear to orbit within partial or complete rings formed from particles blasted off their surfaces by impacts of micrometeoroids.

Sodium Salts detected

Picture

Cassini discovered the water-ice jets in 2005 on Enceladus. These jets expel tiny ice grains and vapor, some of which escape the moon's gravity and form Saturn's outermost ring. Cassini's cosmic dust analyzer has examined the composition of those grains and found salt within them.