The most common type of asteroid in the inner solar system are carbonaceous (C-type), while the most common type of object in the outer solar system are comets. Carbonaceous asteroids are very rich in carbon and other technologically very valuable elements (rare metals, semiconductors). Comets are mostly made of water ice or other solidified volatiles ($CO_2$, $NH_3$). Saturn's rings are made mostly of water ice.
- Can I assume that Saturn's rings are made of basically the same material as comets?
- Can I assume that carbonaceous asteroids are just comets which have lost most of their volatiles? So that most comet and Saturn ring material would be just as rich in carbon, metals and semiconductors as carbonaceous asteroids, if the volatiles were evaporated.
- I'd appreciate a table with the average elemental composition of comets and Saturn rings (I already have such a table for carbonaceous asteroids).
I'm a big fan of colonization of asteroids, because free space has many advantages for industry over planets. (High-quality vacuum, cryogenic temperatures, zero gravity, lots of space for big structures.) This is exactly what most high-tech instruments (like particle accelerators, superconductors, plasma chambers) need.
To build industry in free space, we need material. A lot of useful material (carbon, transition metals and semiconductors) is in asteroids in the main asteroid belt - especially carbonaceous asteroids. The problem of asteroids is that they are very far apart and a lot of time and $\Delta v$ is needed to go from one asteroid to another. This would limit development of large-scale civilization. Asteroids also lack volatiles like nitrogen compounds, which is a big problem for industry, life support and production of rocket fuel.
Saturn's rings seem very attractive from this perspective. They are very compact (lot of material within low time and $\Delta v$ requirements from each other). They are also rich in volatiles. But I'm not so sure if they are also rich enough in other materials (like carbon, metals and semiconductors) to support the full spectrum of industry and technological civilization.