Space · Moons

Margaret

A moon of Uranus — Uranus's only known prograde irregular moon.

Quick facts

Parent planet

Uranus

Diameter (mean)

20 km

Mass

5.4 × 10¹⁵ kg
7.4e-08 Moon masses

Mean orbital radius

14,345,000 km

Orbital period

1694.8 Earth days

Discovery year

2003

Discoverer

Scott S. Sheppard et al.

Naming origin

Character in Much Ado About Nothing

Surface conditions

Margaret is unique among Uranus's irregular moons in having a prograde orbit — every other Uranian irregular orbits retrograde. The reason is unsettled; the leading hypothesis is that Margaret was captured separately from the retrograde cluster.

Missions and observations

Every Uranus-system mission has had an opportunity to image or characterize Margaret. The list below is the Uranus-system mission catalog; specific Margaret encounters are documented in mission archives.

Mission Year at Uranus Status

Voyager 2

NASA

1986 Completed

Naming etymology

Margaret was a character in Shakespeare's Much Ado About Nothing — a gentlewoman attending Hero, accidentally implicated in the misunderstanding that drives the plot. Adopted by the IAU in 2003.

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.

Last refreshed 2026-05-27 by Titan — new page.