Online Astronomy eText: Satellites (Moons)
The Satellites (Moons) of Saturn: Atlas Link for sharing this page on Facebook
Voyager 1 image of Atlas
Atlas as viewed by Voyager 1 in 1980.

A saucer-shaped moon
     Atlas as viewed by the Cassini spacecraft in 2005-07. On the left, as seen from behind, with North on top; on the right, as seen from below its Equator with the leading edge on the left, from a viewpoint four times closer to the moon. The left image shows a 2 to 3 mile high ridge circling the moon's Equator, while the right image shows that the ridge is much smoother than the regions to the South of it. The Cassini spacecraft imaged similar ridges on Iapetus and Pan, but the cause of the ridges, never before seen on any Solar System object, is a mystery. (Planetary Photojournal)

Position of Atlas relative to Saturn's rings
     Atlas lies well inside the thin twisted F-ring, which is controlled by gravitational interactions with Pandora and Prometheus. In a similar fashion, Atlas helps define the outer edge of Saturn's A-ring system, which lies just inside its orbit. (Planetary Photojournal)

Data for Atlas

Discovered by R. Terrile (from Voyager 1 photos) in 1980
Named after one of the sons of Iapetus
Orbital size 137,700 km (approximately 85,500 miles)
Orbital eccentricity 0%
Orbital inclination 0.3 degrees
Orbital period 0.6019 days (about 14 1/2 hours)
Rotation period unknown
Diameter 40 x 20 km (25 x 15 miles)
Mass, surface gravity and density unknown
Albedo (reflectivity) 90% (surface probably covered with fairly bright ice)
Surface temperature probably about 330 Fahrenheit degrees below zero
Controls outer edge of "A" ring by "shepherd moon" interaction
Orbit probably controlled by a 2 to 3 resonance with Mimas