Moonlets are the results of gravitational distortions within the rings. Due to their concentrated mass from clumped up ringroids, they aide in the production of propeller formations, being found near the centres of them, however they can be found outside of propellers also.
Being collections of large ringroids that have been clumped together to form a larger body. The clumping together of the minerals within the ringroids produces a density of minerals way higher than usually found in ringroids, thus creating a significantly hardier structure, and as a result becomes impervious to the tools that you have access to purchase.
Locating Moonlets
Moonlets can be found near the centre of propellers, or can be found randomly elsewhere in the rings.
They can come in small and large sizes, and sometimes they may contain hollowed formations, whether naturally formed or dug out by someone else.
Usage
All moonlets will act as astrogation points once found, and can be updated accordingly. Regardless of whether you may find use with them otherwise, or they're by a good vein, they can always be a free astrogation point regardless.
Some moonlets will be hollow. Hollow small moonlets can be a uranium cave, or hold home to the space bar. Hollow big moonlets house the artist's atelier and spelunker caves. These can hold items to be looted, places to stay, and/or inclusions to the ring's lore.