Cassini Mission Science Overview

Cassini Mission Science

Before Cassini, we had only brief glimpses of the discoveries awaiting us at Saturn. Pioneer 11 and Voyagers 1 and 2 conducted flybys decades ago, taking pictures, measurements and observations as they zoomed past. These missions shed new light on Saturn's complicated ring system, discovered new moons and made the first measurements of Saturn's magnetosphere. But these quick encounters didn't allow time for more extensive scientific research.
Cassini changed all that. It began the first in-depth, up-close study of Saturn and its system of rings and moons in 2004. It became the first spacecraft to orbit Saturn, beginning a mission that yielded troves of new insights over more than a decade. The Saturnian system proved to be rich ground for exploration and discoveries, and Cassini's science findings changed the course of future planetary exploration.
"We're looking at a string of remarkable discoveries -- about Saturn's magnificent rings, its amazing moons, its dynamic magnetosphere and Titan's surface and atmosphere. Some of the mission highlights so far include discovering that Titan has Earth-like processes and that the small moon Enceladus has a hot-spot at its southern pole, plus jets on the surface that spew out ice crystals, and liquid water beneath its surface." - Linda Spilker, Cassini Project Scientist


  • Determine temperature field, cloud properties and composition of the atmosphere.
  • Measure global wind field, including wave and eddy components; observe synoptic cloud features and processes.
  • Infer internal structure and rotation of the deep atmosphere.
  • Study diurnal variations and magnetic control of ionosphere.
  • Provide observational constraints (gas composition, isotope ratios, heat flux) on scenarios for the formation and evolution of Saturn.
  • Investigate sources and morphology of Saturn lightning (Saturn electrostatic discharges, lightning whistlers).


  • Determine abundances of atmospheric constituents (including any noble gases); establish isotope ratios for abundant elements; constrain scenarios of formation and evolution of Titan and its atmosphere.
  • Observe vertical and horizontal distributions of trace gases; search for more complex organic molecules; investigate energy sources for atmospheric chemistry; model the photochemistry of the stratosphere; study formation and composition of aerosols.
  • Measure winds and global temperatures; investigate cloud physics and general circulation and seasonal effects in Titan's atmosphere; search for lightning discharges.
  • Determine physical state, topography and composition of surface; infer internal structure.
  • Investigate upper atmosphere, its ionization and its role as a source of neutral and ionized material for the magnetosphere of Saturn.


  • Determine the configuration of the nearly axially symmetric magnetic field and its relation to the modulation of Saturn kilometric radiation.
  • Determine current systems, composition, sources and sinks of the magnetosphere's charged particles.
  • Investigate wave–particle interactions and dynamics of the dayside magnetosphere and magnetotail of Saturn, and their interactions with solar wind, satellites and rings.
  • Study effect of Titan's interaction with solar wind and magnetospheric plasma.
  • Investigate interactions of Titan's atmosphere and exosphere with surrounding plasma.


  • Study configuration of rings and dynamic processes (gravitational, viscous, erosional and electromagnetic) responsible for ring structure.
  • Map composition and size distribution of ring material.
  • Investigate interrelation of rings and satellites, including embedded satellites.
  • Determine dust and meteoroid distribution in ring vicinity.
  • Study interactions between rings and Saturn's magnetosphere, ionosphere and atmosphere.


  • Determine general characteristics and geological histories of satellites.
  • Define mechanisms of crustal and surface modifications, both external and internal.
  • Investigate compositions and distributions of surface materials, particularly dark, organic rich materials and low-melting-point condensed volatiles.
  • Constrain models of satellites' bulk compositions and internal structures.
  • Investigate interactions with magnetosphere and ring system and possible gas injections into the magnetosphere.

For questions and comments, visit the PDS Cassini Contact Page