Phobos (moon of Mars)

Document v1 · published by Koskamo · updated 2026-10-04

Phobos is a natural satellite of Mars in the NASA/JPL Solar System Dynamics planetary satellite tables.

Planet: Mars
Satellite: Phobos
Satellite code: 401
GM: 0.0007087 ± 0.0000006 km³/s² (ephemeris MAR097)
Mean Radius: 11.08 ± 0.04 km (reference 1)
Mean Density: 1.872 ± 0.076 g/cm³ (NASA note: Mean Density is derived from the specified GM and Mean Radius.)
Ephemeris: MAR099
Reference frame: Laplace
Epoch (TDB): 2000-01-01.5
Semi-major axis a: 9375. km
Eccentricity e: 0.015
Argument of periapsis ω: 216.3 deg
Mean anomaly M: 189.7 deg
Inclination i: 1.1 deg
Longitude of ascending node: 169.2 deg
Sidereal period P: 0.3187 days
Argument of periapsis precession period: 1.1 yr
Longitude of ascending node precession period: 2.3 yr
Laplace-plane pole right ascension: 317.7 deg
Laplace-plane pole declination: 52.9 deg
Laplace-plane tilt: 0.0 deg
Mean elements reference: 7

Source and provenance

Original source: ssd.jpl.nasa.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: NASA/JPL Solar System Dynamics planetary satellite mean elements and physical parameters (ssd.jpl.nasa.gov/sats), a work of the US government (public domain in the United States)

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Version history

Published by Koskamo2026-10-04
Version 1