Apparatus Cassini during the flyby on December 23, 2012 photographed the Dion (Saturn) from a distance of 249 238 km Imagery in the visible range was performed using the long-focus camera and filters subsystem ISS (Imaging Science Subsystem). Although Dion consists mainly of water ice and stone, the resulting images are nevertheless noticeable slightly colored area - take a look for yourself.

Dion was discovered by Giovanni Cassini in 1684, but its modern name thanks to John Herschel. Probably, the color of a surface of this moon of Saturn gives the play of light on ice ridges and cliffs. Contributing to weak staining can give strongly rarefied atmosphere diones containing water vapor and single (about 90 particles per liter) oxygen ions.

Recently discovered signs of the atmosphere at the satellite of Saturn initially caused surprise. As such a small body with a diameter of 1120 km and weighing 67 times smaller than the moon can keep gaseous envelope? Further study showed that the highly rarefied atmosphere diones formed quite differently than planets.

Dion removed from Saturn on average 377 400 km, which is slightly less than the distance from Earth to the moon. Powerful magnetic field Saturn captures high-energy particles of the solar wind. In the magnetosphere they are unevenly distributed, forming areas with high concentrations of particles, such radiation belts of the Earth.

The orbit of dione is located near one of such zones. Its surface is bombarded by a high-energy particles, which beat out of water ice individual molecules and ions. Neutral molecules are fast disappearing, and charged particles are held by a magnetic field, and dione supported thin ionized atmosphere.

Dion similar to another satellite of Saturn - ray, most of the weight is water ice. In addition to the oxygen in the atmosphere Rhea was discovered carbon dioxide, but it should not be regarded as signs of life. Water and oxygen are found in the Solar system many astronomical objects, and carbon dioxide easily formed in the space outside of biological processes.

The system satellites of Saturn is considered the most difficult. To date, confirmed the existence of sixty-two natural satellites with a known mass and orbit. More than half of them opened in the last decade.

By the beginning of the XXI century was known only eighteen satellites of Saturn. Before the start of the mission of the Cassini-Huygens was able to detect even thirteen. Directly by the apparatus Cassini discovered eight satellites whose orbits are not available for observations from the Ground areas.

On the success of the scientific program of the station Cassini was extended twice. The planned date for completion of the mission - September 2017.