Uranus · natural satellite

Umbriel

A dark, cratered moon

Umbriel is darker than the other large Uranian moons. Voyager 2 photographed its southern hemisphere, including a conspicuous bright ring near the equator.

Mean diameter: 1,169.4 km
Mean orbital distance: 265,986 km from centre
Orbital period: 4.144 Earth days

Umbriel · NASA spacecraft imagery — NASA/JPL · Image source ↗

Compared with our Moon

Umbriel · 1,169.4 km

Moon · 3,474.8 km

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

Orbit & discovery

Surface gravity: 0.249 m/s²
Discovery: 1851
Discoverer / team: W. Lassell
Provisional designation: —
JPL satellite ID: 702
Orbital eccentricity: 0.004
Inclination: 0.1 degrees

Inclination reference: equatorial. Mean-element epoch: 2000-01-01.5 TDB · URA182.

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: 584.7 ±2.8 [1]
GM · km³/s²: 85.1 ±1.9 [URA111]
Density · g/cm³: 1.523 ±0.041 [*]

Missions in the Uranus system · 1 records

1 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

Voyager 2

August 20, 1977 · UTC

Lockheed Martin · Titan IIIE

1 records from the complete 9,386‑record production catalogue.

Sources & measurements