Short answers, pulled from the story.
William Herschel recorded the discovery of Mimas on the 17th of September 1789 using his massive 40-foot telescope. This observation marked the first time humanity had seen this moon, though it remained unnamed for decades after its initial detection.
Mimas has a mean diameter of approximately 396 kilometers and consists mostly of water ice with only a small amount of rock mixed within. Its density sits at just 1.15 grams per cubic centimeter while tidal forces cause it to become noticeably oblate.
The Herschel crater spans 138 kilometers across the surface of Micas and measures almost one-third of the parent body's total diameter. If Earth possessed a crater of equivalent scale it would span over 600 kilometers wider than Australia.
Scientists at the Southwest Research Institute identified a tidal heating model in 2022 that produced an internal ocean without visible surface cracks. They estimated the ocean sits 20 to 30 kilometers below the surface and must be less than 25 million years old to explain the lack of geological activity.
Pioneer 11 flew past Saturn during 1979 achieving its closest approach to Micas on the 1st of September 1979 at a distance of 104,263 kilometers. The Cassini orbiter entered orbit around Saturn in 2004 allowing multiple close imaging sessions including a particularly detailed encounter on the 13th of February 2010 when Cassini passed within 9,800 kilometers of the moon's surface.