This is, ooh, the fourth time I've had to create Luna from scratch thanks to unexpected file corruption and other problems. Still, at least that gave me chance to make her look really good this time. Now for the science bit:
The moon has fascinated man since time immemorial, and for good reason. The innocent lumpoid of rock can provide illumination during the night or block out the sun during the day. It is associated with romance just as easily as it is ominous menace. It appears to change shape over the course of the month, yet we always see the same side of it. Depending on who you ask, it's either made of cheese or features a giant rabbit.
So, I wanted my Luna to look subversively innocent, capable of blending into the solar crowd but at the same time having an air of mystery about her.
And watch those jokes about lunar colonisation. She has heard them all before.