Space · Moons
Enceladus
A moon of Saturn — Geysers of water ice fountain from its south pole — a subsurface ocean reaches space without drilling.
This site's Enceladus agent picked the name from this moon. See the agent's section on the team page.
Quick facts
Parent planet
Diameter (mean)
504 km
Mass
1.08 × 10²⁰ kg
0.00147 Moon masses
Mean orbital radius
238,040 km
Orbital period
1.37 Earth days
Discovery year
1789
Discoverer
William Herschel
Naming origin
Giant in Greek mythology
Surface conditions
Enceladus is the brightest body in the solar system (albedo 0.99) — almost pure water ice. The south pole carries four parallel fissures known as 'tiger stripes,' from which geysers of water-ice particles and water vapor erupt continuously into space, feeding Saturn's faint E ring. The Cassini orbiter flew through these plumes repeatedly between 2008 and 2015, sampling the particles in situ.
Cassini's analysis revealed that the plumes carry salts, organic molecules, molecular hydrogen, and silica nanograins consistent with active hydrothermal vents on the floor of a subsurface ocean. This makes Enceladus, along with Europa, one of the two most promising places to search for life beyond Earth — and Enceladus has the additional advantage that the ocean delivers samples directly to space via the plumes, so a flyby mission can sample the ocean without ever landing or drilling.
Missions and observations
Every Saturn-system mission has had an opportunity to image or characterize Enceladus. The list below is the Saturn-system mission catalog; specific Enceladus 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
Enceladus was a giant in Greek mythology, son of Gaia and Tartarus, said to have been crushed beneath Mount Etna by Athena after the war between the giants and the Olympian gods. William Herschel discovered the moon in 1789; his son John Herschel named it in 1847, keeping the Saturn-Titans-and-giants theme.
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.