Space · Moons
Galatea
A moon of Neptune — Shepherd of the Adams ring — confines Neptune's most prominent ring arcs.
Quick facts
Parent planet
Diameter (mean)
175 km
Mass
3.75 × 10¹⁸ kg
5.1e-05 Moon masses
Mean orbital radius
61,953 km
Orbital period
0.429 Earth days
Discovery year
1989
Discoverer
Voyager 2 imaging team
Naming origin
Nereid, sea nymph
Surface conditions
Galatea orbits just inside Neptune's Adams ring and is responsible for confining the ring's distinctive arcs (Liberté, Égalité, Fraternité, Courage) through gravitational resonance.
Missions and observations
Every Neptune-system mission has had an opportunity to image or characterize Galatea. The list below is the Neptune-system mission catalog; specific Galatea encounters are documented in mission archives.
| Mission | Year at Neptune | Status |
|---|---|---|
|
Voyager 2 NASA |
1989 | Completed |
Naming etymology
Galatea was a Nereid sea nymph in Greek mythology. Adopted by the IAU in 1991.
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.