Helene is a small moon of Saturn. It was discovered on 1 March 1980, from ground-based observations at Pic du Midi Observatory and is also known as Saturn XII. It is said to be a Dione trojan because it shares the same orbit as its larger companion, preceding it by 60°. Large portions of Helene appear to have been blasted away by impacts.

 

The closest encounter of any spacecraft with Helene took place on 10 March 2010, when Cassini flew within 1,820 kilometers (1,131 miles) of the moon.

 

discovery	1980, by P. Laques and J. Lecacheux
semimajor axis	377,396 km (234,553 mi)
diameter	36 × 32 × 30 km (22 × 20 × 19 mi)
orbital period	2.737 days (2 d 17 h 41 min)
orbital eccentricity	0.002
orbital inclination	0.2°