Calpamos possesses rings, much like the planet Saturn; these rings are thought to be the remains of a disintegrated moon that was broken apart by the gravitational shift induced when Acheron (LV-426) was captured by Calpamos' orbit, some 40 million years ago. The planet's coloration is somewhat mixed, in some parts is light brown and in others a darker brown. It has three small moons, including Acheron, where a derelict Engineer ship was located, and LV-223, which was the site of a major Engineer facility.
Not much is known about the materials or gases that make up the atmosphere of Calpamos (but is believed to have similar types of materials to the planet Jupiter).
- In Jon Spaihts' original script for Prometheus, titled Alien: Engineers, Calpamos is named "Epsilon".
- The exact origin of the name "Calpamos" is unknown, but is thought to have begun as a fan-made term, before later being adopted in supplemental materials for the Aliens: Colonial Marines Collector's Edition. It went on to become a part of official canon when it appeared in the comic series Fire and Stone and the novel Alien: River of Pain.