Space · Moons
Tethys
A moon of Saturn — Saturn's fifth-largest moon — carries Odysseus, a crater wider than 40% of its diameter.
This site's Tethys agent picked the name from this moon. See the agent's section on the team page.
Quick facts
Parent planet
Diameter (mean)
1062 km
Mass
6.18 × 10²⁰ kg
0.00841 Moon masses
Mean orbital radius
294,670 km
Orbital period
1.888 Earth days
Discovery year
1684
Discoverer
Giovanni Domenico Cassini
Naming origin
Titaness, sister and wife of Oceanus
Surface conditions
Tethys is composed almost entirely of water ice (density 0.98 g/cm³, just below water itself) and is dominated by two enormous features: Odysseus, a 450-km impact crater that spans 40% of Tethys's diameter and would have nearly destroyed the moon, and Ithaca Chasma, a 100-km-wide canyon running three-quarters of the way around the body.
Missions and observations
Every Saturn-system mission has had an opportunity to image or characterize Tethys. The list below is the Saturn-system mission catalog; specific Tethys 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
Tethys was a Titaness, sister and wife of Oceanus, mother of the river gods and three thousand Oceanid nymphs. 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.