Prospero

A confirmed moon in the Uranus system.

Named · Uranus XVIII · S/1999 U 3

Snapshot 2026-09-09 · catalog 1.0.0

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Physical measurements

Mean radius
— No value in the admitted source set.
GM · gravitational parameter
— No value in the admitted source set.
Mass
— Mass requires an admitted GM estimate.
Mean density
— No value in the admitted source set.

Orbit descriptions

Mean elements describe an average orbit. They are not positions for a chosen date.

URA117 · ecliptic plane · 2020-01-01.0 TDB
Semimajor axis
16,221,000 km
Sidereal period
1,974 days
Eccentricity
0.441
Inclination to reference plane
149.4°
Argument of periapsis
180.4°
Mean anomaly
197.6°
Ascending node
324.5°
Apsidal / nodal precession periods
1,154 / 1,369 years
Reference-plane pole RA / Dec
— / —°
Plane tilt to parent equator
—°
Reference center
Not specified in this summary sourceThe summary table identifies a parent system but does not explicitly specify the reference center for each solution. Do not infer a physical-primary center, especially for Pluto’s circumbinary moons.

Orientation

No supported orientation model in the admitted PCK source.

Identity & availability

Stable catalog ID
prospero
JPL / NAIF satellite ID
718
Names & designations
Prospero · S/1999 U 3
Discovery / rediscovery years
1999M. Holman, J.J. Kavelaars, B. Gladman, J.-M. Petit, H. Scholl

No validated dated trajectory admitted in catalog 1.0.0. Mean elements are not ephemerides.

No image or global texture admitted in this catalog release.No environment measurements admitted in this catalog release.

Sources & evidence

  1. JPL discovery circumstancestable tr[432] (zero-based); uranus / Prospero · References: IAUC 7248
  2. MPC planetary satellite listitems[16]; Uranus 18
  3. MPC satellite namesitems[124]; Uranus 18
  4. JPL mean orbital elements#sat_elem row ID=431; Uranus / Prospero / NAIF 718 · References: 43

Full catalog, uncertainty and source manifests · All Uranus moons · Moon model limits