spacer spacer spacer
spacer spacer spacer
spacer
NASA Logo - Jet Propulsion Laboratory
+ View the NASA Portal
Search JPL
JPL Home Earth Solar System Stars & Galaxies Technology
Voyager - Celebrating 25 Years of Discovery
spacer
spacer spacer spacer
spacer
 
 
New Satellites
 
 
Interstellar Science
Planetary Voyage
 


More About Saturn

The Rings

Titan

New Satellites


Other Satellites


The Magnetosphere
"

 
Science News Archive
Voyager's Thirty Year Plan
Heliocentric View of Trajectories
Hyperbolic Orbital Elements
Publication Bibliography
Principal Investigator Home Institutions
JupiterSaturnUranusNeptunePlanetary Voyage

New Satellites

Collage of Saturn's smaller satellites
Collage of Saturn's smaller satellites (Click on the image for a larger view)

Before the first Voyager encounter, astronomers believed Saturn had 11 satellites. Now they know it has at least 17 and possibly more. Three of the 17 were discovered by Voyager 1. Three additional possible satellites have been identified in imaging data since the Voyager 2 encounter. (Three others were discovered in ground-based observations.)

The innermost satellite, Atlas, orbits near the outer edge of the A-ring and is about 40 by 20 kilometers (25 by 15 miles) in size. It was discovered in Voyager 1 images.

The next satellite outward, Prometheus, shepherds the inner edge of the F-ring and is about 140 by 100 by 80 kilometers (90 by 60 by 50 miles). Next is Pandora, outer shepherd of the F-ring, 110 by 90 by 80 kilometers (70 by 55 by 50 miles). Both shepherds were found by Voyager 1.

Next are Epimetheus and Janus, which share about the same orbit -- 91,000 kilometers (56,600 miles) above the clouds. As they near each other, the satellites trade orbits (the outer is about 50 kilometers, or 30 miles, farther from Saturn than the inner). Janus is 220 by 200 by 160 kilometers (140 by 125 by 100 miles), and Epimetheus is 140 by 120 by 100 kilometers (90 by 70 by 50 miles). Both were discovered by ground-based observers.

One new satellite, Helene, shares the orbit of Dione, about 60 degrees ahead of its larger companion, and is called the Dione Trojan. It is about 36 by 32 by 30 kilometers (22 by 20 by 19 miles). Helene was discovered in ground-based photographs.

Two more satellites are called the Tethys Trojans because they circle Saturn in the same orbit as Tethys, about 60 degrees ahead of and behind that body. They are Telesto (the leading Trojan) and Calypso (the trailing Trojan). Both were found in 1981 among ground-based observations made in 1980. Telesto is 34 by 28 by 26 kilometers (21 by 17 by 16 miles) and Calypso is 34 by 22 by 22 kilometers (21 by 14 by 14 miles).

There are three unconfirmed satellites. One circles Saturn in the orbit of Dione, a second is located between the orbits of Tethys and Dione, and the third, between Dione and Rhea. All three were found in Voyager photographs, but were not confirmed by more than one sighting.

 

 
spacer
spacer
This page was last updated January 14, 2003
spacer
spacer spacer spacer
spacer spacer spacer
spacer spacer spacer
spacer
FIRST GOV   NASA Home Page Site Manager: Andrea Angrum
Webmaster: Enrique Medina
spacer
spacer spacer spacer
spacer spacer spacer
Jet Propulsion LaboratoryCalifornia Institute of Technology HomeMissionScienceSpacecraftNewsImagesMultimediaKidsEducation CopyrightFAQFeedbackSite Map