Letters of the alphabet: Also makes no sense. There was a theory that Argon = A, that there was an unreleased B model (Bismuth or Barium or something), Carbon = C, etc. (Similar to Intel's MMORPG-inspired Alchemist --> Battlemage --> Celestial...) Hydrogen broke this notion.
It's just completely incoherent.
Also, the biggest being Astra is a bit confusing. Sol is also a star.
Furthermore, unless you know they’re supposed to be ordered by size you can’t know which is best.
I don't think these are as difficult as you're making them sound? I think the majority of people who will care what model they're using will know "lunar", "terrestrial", "solar", "astronomy" etc?