Acheron (LV-426) is one of three known moons that orbit Calpamos, which is the fifth planet from the star Zeta 2 Reticuli located in the Zeta Reticuli system, 39 light years away from Earth. The moon is christened by human colonists as Acheron. The moon was given its common name by the early human colonists who settled there. The main colonist base, Hadley's Hope, housed 158 people.


Early human interactionEdit

LV-426 was first detected by Human astronomers on May 14, 2039. The moon was subsequently catalogued by a French deep-space probe. The first comprehensive survey was not carried out until the 2130s.

Before colonizationEdit

LV-426 was described as being almost primordial. It's atmosphere consisted of inert nitrogen, a high concentration of carbon dioxide crystals and methane. The moon was highly unstable with volcanic activity. The main crust of the moon was formed mostly out of igneous rocks with a surface temperate of absolute zero. Needless to say, LV-426 was inhospitable to human life. Being so primitive, LV-426 wasn't capable of supporting any forms of life. It had no indigenous life. The moon was home to a crashed alien derelict vessel, the Derelict, however. It's relationship to the planet is unknown. There may have been a Space Jockey base at one point or it was the homeworld of the alien eggs the ship carried in it's cargo hold.


By 2367, Acheron was the home to Hadley's Hope, a human colony. Before this the atmosphere of the small moon was completely change so LV-426 was capable of supporting human life. The process of actually terraforming Acheron took around a decade and required the building of thirty atmosphere processors which would replace the dangerous gases in the atmosphere with oxygen and hydrogen. After the atmospheric processors had successfully created an atmosphere in which humans could live, Hadley's Hope was constructed and the colonists moved in. Even though the planet was now habitable, it had ravenging winds and a rocky surface. More than a century after it's discovery, the derelict ship was still there, located beyond the Ilium Range. It had been damaged due to lava and volcanic eruptions but it was still there. It was found by the colonists and soon the colonists became infected and Hadley's Hope was overrun. After a squad of Starfleet Marines attempted to rescue the colonists of Hadley's Hope, they inadvertently damaged one of the atmospheric processors. It exploded with a force of 40 megatones, vaporizing an area the size of Nebraska. The twenty nine atmospheric processors remained stable. However during the second Starfleet Marine Corps squad's investigation to LV-426 reveals that the Xenomorphs had in fact survived the nuclear explosion from the atmosphere processor. It would soon be discovered that the nuclear explosion had actually failed to either eliminate the entirety of Hadley's Hope nor clear out the Xenomorph infestation and a second marine expedition to the planet would prove far more dangerous than Ripley's team had encountered.

Terrain and climateEdit

Acheron has a 12,201 km diameter at its quadrant points QBR 157 052 and has a molten lava base. The planet maintains a gravitational field equivalent to 0.86 of that on Earth, implying the moon is made of incredibly dense material given its small size. When first discovered, the moon was highly unstable with volcanic activity. The main crust was formed mostly out of igneous rocks. The moon's geological structure has led to the conclusion it is a recently captured body, entering Calpamos' orbit within the last 40 million years or so. Indeed, the rings around Calpamos itself are thought to be the remnants of a previous satellite that was broken apart by the gravitational shift induced by Acheron's arrival.

The planetoid's indigenous atmosphere was described as "primordial", consisting mainly of nitrogen, water vapor, carbon dioxide, trace particles of oxygen and small concentrations of methane and ammonia. It is constantly racked by strong winds, although the moon is too small for potentially dangerous very large storms to form. Needless to say, LV-426 under native conditions was inhospitable to human life.

Geographical featuresEdit

The Ilyium Range is a mountain range on the Acheron moon, located near to where the Nostromo discovered an abandoned alien vessel in 2367.


"It's a rock. No indigenous life."

Federation representative regarding LV-426

Acheron has no indigenous life forms, and it is not the Xenomorph homeworld; it was simply a planet upon which an Engineer ship, containing Xenomorph Eggs and possibly live subjects as well, crash-landed. According to Federation surveys, Acheron was simply a dead rock.


Acheron is best known for the terraforming colony of Hadley's Hope, established on the moon in the 2350s for the purpose of processing the planetoid's atmosphere to create a suitable environment for large-scale human habitation.

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