[Insert tid bits about planets in the Sunrider Universe here. Maybe the number of planets that have been colonized.]
"The class level denotes general suitability for human colonization.
A class 11 planet's pretty comfortable, just a bit more habitable than modern Earth. Class 8 isn't as ideal, but generally survivable without any terraforming. (Kinda like Canada.) Class 7 is kinda like Russia or Egypt (very cold or dry, but the best parts are habitable.)
Class 3 (Tydaria) is like modern Mars. Habitation is only possible in limited terraformed areas or in capsules. Otherwise, most of the planet's surface is deadly without life support equipment.
Class 1 is pretty much like Mercury. Permanent human habitation is impossible, aside from mining or research facilities."
- New Eden