Thedus is a planet in the Outer Rim Territories that is rich with natural resources. The Weyland-Yutani corporation mined Thedus extensively throughout the twenty-second century. Before 2122, the USCSS Nostromo traveled here to retrieve an orbital refinery, which was processing 20,000,000 tons of mineral ore. Two days before the Nostromo left the planet, its original science officer was replaced with Ash.[citation needed]