Acheron (LV-426)
Astrographical information
Location Zeta II Reticuli, orbiting Calpamos
Classification Moon
Physical information
Diameter 1,200 km
Terrain Rocks
Temperature -60 - +40°C
Points of interest The Derelict
Hadley's Hope
Chronological information
First appearance Alien
Last appearance Alien: Isolation

LV-426 is one of three known moons orbiting the planet Calpamos, located in the Zeta II Reticuli system, 39 light years from Earth. The moon is christened by human colonists as Acheron.

Basic CharacteristicsEdit

LV-426 is a planetoid with 1200km diameter (see footnote), rotation period about 2 hours, and surface gravity 0.86.

Terrain & ClimateEdit

LV-426 terrain

The surface of LV-426.

The original surface before terraforming was lava base rock, with some ongoing volcanic activity.

Before atmospheric processing began, its atmosphere was reported by USCSS Nostromo crew member Ash to be primordial and inert, containing nitrogen, high concentration of CO2 crystals, methane and trace elements. Dust and turbulence created a murky atmosphere with little surface light and poor visibility. Originally the atmosphere at the surface was deep cold.

Geographical featuresEdit

The Ilium Range is a mountain range, where the derelict spacecraft was discovered.


In 2122, the commercial tow freighter Nostromo awakened its crew from stasis to investigate a mysterious signal coming from a nearby planetoid, as per company protocol. Though the Nostromo's shuttle was severely damaged while landing on LV-426, the crew's exploration team consisting of Captain Dallas, Kane and Lambert proceeded to explore the planetoid's surface and eventually discovered the Derelict spacecraft that was responsible for transmitting the signal. While exploring the Derelict's interior, the crew came across the fossilized remains of the ship's pilot and thousands of eggs stored within the ship's cargo hull. Kane was impregnated by a facehugger that emerged from one of the eggs and was taken to the Nostromo for treatment. The Nostromo's shuttle soon lifted off again, but the creature implanted an embryo in Kane which birthed from his chest in space, eventually leading to the Nostromo 's destruction.

Approximately thirty-six years after the USCSS Nostromo made contact with LV-426, the Weyland-Yutani Corporation established the terraforming colony, Hadley's Hope, on LV-426, using an atmospheric processor to make the planet's atmosphere breathable and up to habitable temperatures.

Another twenty years later, the Jordan family sent to investigate a set of coordinates on company orders, discovered the Derelict, apparently untouched since the Nostromo incident fifty-seven years earlier. A facehugger impregnated the father, Russ, when he and his wife explored the Derelict spacecraft. Under orders from Carter Burke, the colonists investigated the Xenomorph eggs and a large number of colonists were 'facehugged' so that the species could be studied. Four dead facehuggers were kept preserved, and two live ones were removed before embryo implantation, at the cost of the lives of their hosts. However, the humans who were impregnated released chestbursters which matured and established a hive in sub-level 3 of the Hadley's Hope atmosphere processor. The Xenomorphs killed or captured, cocooned and impregnated many of the colonists, and one of the Xenomorphs molted into a Queen and started producing more eggs. The remaining humans barricaded themselves into the colony complex and fought with small arms and the colony's seismic survey charges but to no avail. The Aliens captured or killed outright all but one of the colonists, a little girl.

A short while after this, a Colonial Marines squad, including Lieutenant Ellen Ripley, arrived on LV-426 to investigate the loss of communication. After many battles with the Xenomorphs, the hive was destroyed when the atmospheric processor's power source exploded. Ripley, Newt (the sole surviving colonist), Corporal Dwayne Hicks, and an android ("Bishop") escaped LV-426 in time onboard the USS Sulaco. Unknown to them, the Queen and a facehugger had managed to get aboard; the former was ejected into space by Ripley through the airlock.


  • The designation LV-426 is not scientifically accurate. Lima Vector or Lagrange Vector and 3 coordinates to specify which moon of a planetary body is being referred to. In reality this is not a correct designation (as a myriad of satellites around any planet could have the same three digit number (which is not a vector notation).

The correct astronomical nomenclature for LV-426 would be: S/2039 (ζ2 Ret IV) 2.

S: for designating a Satellite (Moon)

2039: the year of discovery

(ζ2 Ret IV): The planet it orbits (in this case the fourth planet of Zeta 2 Reticuli)

2: As the 2nd new moon discovered and designated in that year, around that planetary body.

After it is named (and if the planet is named) it would be: (ζ2 Ret) Calpamos II Acheron

  • The name "Acheron" is likely a reference to the branch of the river Styx in Greek mythology.
  • Source materials differ widely on the diameter of the planetoid: A figure of 1,200 km is given in the movie Alien, the film's shooting screenplay, and in the accompanying novel. The Aliens: Colonial Marines Technical Manual (a supplementary book to Aliens) gives a figure of 12,201 km, which is essentially the same size as Earth and would hardly make it describable as a "tiny planetoid" as in the Alien movie and script. The original script by O'Bannon and Shusett before rework by Hill and Giler has the diameter at 120km.


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