So I'm pretty sure I know what happened. My civilization that resides on Earth is a clone of the Terran Alliance, so I guess when the solar system is set to "Sol", it's not actually the Sol system, but one generated from scratch, but with the same planet names and properties, because the continents mapped to my Earth aren't the ones on the Earth. So it's my Earth that doesn't have a moon.
On a side note, isn't the moon a little small? It should be a tad larger than 25% of the diameter of the Earth. (I have to have something to gripe about, right?) 
