Saturn · natural satellite

Epimetheus

Mean diameter: 116.4 km
Mean orbital distance: 151,400 km from centre
Orbital period: 0.697 Earth days

Compared with our Moon

Epimetheus · 116.4 km

Moon · 3,474.8 km

One diameter scale. Circle shapes compare volume-equivalent diameters; irregular moons are not spheres.

Orbit & discovery

Surface gravity: 0.01 m/s²
Discovery: 1977, 1980
Discoverer / team: J. Fountain, S. Larson (1977), D. Cruikshank (1980)
Provisional designation: S/1980 S3
JPL satellite ID: 611
Orbital eccentricity: 0.02
Inclination: 0.3 degrees

Inclination reference: Laplace. Mean-element epoch: 2000-01-01.5 TDB · SAT415.

Diameters use volume-equivalent mean radii, including for irregular bodies. Mean orbital elements describe an orbit; they are not live positions. Missing physical measurements remain unavailable.

Physical measurements & uncertainties

Mean radius · km: 58.2 ±1.2 [1]
GM · km³/s²: 0.03514 ±0.00002 [SAT415]
Density · g/cm³: 0.6375 ±0.0394 [*]

Missions in the Saturn system · 5 records

5 launches · 0 linked events

These records cover the planetary system. A system mission did not necessarily visit this moon. Dedicated targets are marked separately; programme events include the journey and briefings. Launch outcomes do not establish arrival, landing success or present spacecraft operation.

Dedicated targets only

PLANETARY SYSTEM · UPCOMING