S/2009 S 1

S/2009 S 1 is a moonlet embedded in the outer part of Saturn's B Ring, orbiting 117,000 km away from the planet. The moonlet was discovered by the Cassini Imaging Team during the Saturnian equinox event on 26 July 2009, when the Cassini spacecraft imaged the moonlet casting a 36 km-long shadow onto the B Ring. With a diameter of 300 m, it is most likely a long-lived solid body, which would count it as the smallest and innermost known moon of Saturn.

Discovery
was first identified by the Cassini Imaging Team led by Carolyn Porco, in a single image taken by the Cassini spacecraft approximately 296,000 km from Saturn on 26 July 2009 11:30 UTC. The moonlet was discovered during Saturn's 2009 equinox, when it cast an approximately 36 km-long shadow on the planet's B ring.

Characteristics
Based on the shadow's width, the Cassini Imaging Team infer a diameter of 300 m for. The presence of a shadow suggests that the is most likely a solid body large enough to have existed since the formation of the B ring. This particular moon is one of the smallest moons of Saturn that has been directly imaged.

is located about 650 km interior to the edge of the B ring, corresponding to a radial distance of 116,914 ± 17 km from the center of Saturn. The moonlet protrudes 150 m above the B ring plane, which has a vertical thickness of 5 m for comparison.

Although it is embedded in the B ring, does not appear to produce extensive, propeller-shaped disturbance features unlike the propeller moonlets in Saturn's A ring. This may be because the B ring is very dense at the moonlet's location, which would hinder the formation of visible propeller gaps around the moonlet.