New Planets in Solar Echoes

Some RPG game systems detail entire cities, with a full book dedicated to everything you'd ever need to know about adventuring in that city. These books covered the various races that would be commonly found within the city, talked about the major geographic areas, the culture of the people, and the economy. A number of ideas were listed regarding possible adventure seeds—short summaries of plots that could be expanded and explored by GM's looking to flesh out a campaign, or fill the gaps between adventures. These books made a simple setting into a robust world that a GM could immerse his players in for an entire campaign if he desired! I have recently taken up the task of preparing a new product based on the original Explorer's Pack for Solar Echoes. In the original, we detailed 4 different planets, and included a new alien lifeform with each. Each planet had basic details and some missions seeds for ideas. Though I'm not going to make this new product into a huge book, I am spending a little more time on detailing a single planet. The product will focus on that planet alone, including planet details, a new alien lifeform, and a short adventure involving that new lifeform, plus possible maps and icons to use in the mission. I've already got a good start, but what types of things would you like to see included in the planet details?