S/2009 S 1 is a moonlet embedded in the outer part of Saturn's B Ring, orbiting 117,000 km (73,000 mi) away from the planet.
S/2009 S 1 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 (184,000 mi) 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 (22 mi)-long shadow on the planet's B ring.
Based on the shadow's width, the Cassini Imaging Team infer a diameter of 300 m (1,000 ft) for S/2009 S 1. The presence of a shadow suggests that the S/2009 S 1 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. It is the smallest and innermost known moon of Saturn.
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