From publisher blurb:
The Explorer's Pack includes 4 new, detailed planets, alien lifeforms, and mission scenarios! Adventure lies among the stars, as your team of UG agents investigates dangers and mysteries on distant worlds. The Explorer's Pack contains all you need to create missions on several new planets, including scientific data, historical information, biological examples, and starter mission ideas. Featuring full color planetary artwork by Matthew Hannum and b&w alien lifeform sketches by Andy Mitchell.