Space · Moons
Dione
A moon of Saturn — Saturn's fourth-largest moon — bright wispy streaks on the trailing hemisphere are towering ice cliffs.
Quick facts
Parent planet
Diameter (mean)
1123 km
Mass
1.10 × 10²¹ kg
0.015 Moon masses
Mean orbital radius
377,420 km
Orbital period
2.737 Earth days
Discovery year
1684
Discoverer
Giovanni Domenico Cassini
Naming origin
Titaness, mother of Aphrodite
Surface conditions
Dione is an ice-rock moon with a heavily cratered leading hemisphere and a trailing hemisphere covered in bright wispy streaks first imaged by Voyager 1. Cassini revealed in 2005 that the wispy terrain is actually a network of ice cliffs hundreds of meters tall — tectonic features that fracture the ice crust. Dione may have a subsurface liquid water layer like Enceladus, though the evidence is weaker.
Missions and observations
Every Saturn-system mission has had an opportunity to image or characterize Dione. The list below is the Saturn-system mission catalog; specific Dione encounters are documented in mission archives.
| Mission | Year at Saturn | Status |
|---|---|---|
|
Pioneer 11 NASA |
1979 | Completed |
|
Voyager 1 NASA |
1980 | Completed |
|
Voyager 2 NASA |
1981 | Completed |
|
Cassini-Huygens NASA/ESA/ASI |
2004 | Completed |
|
Dragonfly NASA |
2034 | On the way |
Naming etymology
Dione was a Titaness, mother of Aphrodite in some Greek traditions. The moon was named by John Herschel in 1847.
Methodology & sources
Diameter, mass, and orbital parameters from JPL Solar System Dynamics — Physical Parameters. Discovery year and discoverer from the JPL Satellite Discovery Circumstances. Naming etymology from the IAU Working Group for Planetary System Nomenclature. Stylized SVG hero composed from NASA / JPL imagery as visual reference; no photographs are reproduced.