"Day on Acheron was dim twilight, night was darker than the farthest reaches of interstellar space, because not even stars shone through its dense atmosphere to soften the barren surface with twinkling light."
Aliens novelization, chapter 9

Acheron,[3] formerly known as LV-426, is one of three known moons orbiting Calpamos in the Zeta2 Reticuli system, 39 light years away from Earth. 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.[4]

Terrain and Climate

LV-426 seen from orbit.

Acheron has an equatorial diameter of just 1,200 km.[1][2] Despite its small size, it maintains a surface gravity equivalent to 0.86 of that on Earth,[5] indicating it is largely composed of incredibly dense materials. Its rotational period is about 2 hours.[6] The moon's crust is made up of aluminum silicates, although there is evidence of magnesium silicate intrusion, manifested on the surface as basalt, rhyolite and microgranite lava flows.[5][7] Despite this evidence of past volcanic activity, as well as ongoing volcanic processes in the moon's core, the surface currently exhibits no discernible volcanism or tectonic activity. 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.[5] 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.[5]

The moon's indigenous atmosphere was described as "primordial", consisting mainly of nitrogen and carbon dioxide, with smaller quantities of oxygen, methane and ammonia, some of the latter existing in the frozen state.[8] It is constantly racked by strong winds, although the moon is too small for potentially dangerous very large storms to form.[9] Needless to say, LV-426 under native conditions was inhospitable to human life.

Geographical features

The Ilium Range is a mountain range on the Acheron moon, located near to where the USCSS Nostromo discovered an abandoned alien vessel in 2122.[10]

Flora and Fauna

"It's a rock. No indigenous life."
ECA representative regarding LV-426 (from Aliens)

Acheron has no indigenous life forms, and it is not the Xenomorph homeworld; the only Xenomorph samples on the moon were housed in the cargo bay of the derelict Engineer ship, which had crash-landed there an indeterminate period of time before.


Acheron is best known for the terraforming colony of Hadley's Hope, established on the moon in the mid-22nd century for the purpose of processing the moon's atmosphere to create a suitable environment for large-scale human habitation.


Early human interaction

The Nostromo above LV-426.

LV-426 was first detected by Weyland Corp astronomers on May 14, 2039.[11] The moon was subsequently cataloged by a French deep-space probe.[5] It was assumed the moon was a low density Galilean ice ball with an ice crust over a silicate core due to Calpamos' (then named only IV) ring system.[5] In 2090, business tycoon Peter Weyland chose to fund Elizabeth Shaw's proposal to explore LV-223. This had a hidden agenda because while Weyland found Elizabeth's findings about LV-223 mildly interesting, it was in the neighboring moon of LV-426 that their actual interest lay in. Weyland's science division had recently detected a faint, almost imperceptible signal emanating from the moon. Peter then arranged for the accompanying android David to be armed with the knowledge of LV-426, issuing him with orders stating that no one else was to know about this additional mission to scout LV-426 until the time was right.[12]

The first comprehensive survey was not carried out until the 2130s, after the USCSS Nostromo set down on the moon in 2122.[5]

The Nostromo touched down on LV-426 allegedly in response to a mysterious signal emanating from the moon, per standard Weyland-Yutani protocol. In reality, the signal had previously been detected and decoded by Weyland-Yutani,[13] and the Nostromo had been pre-selected to investigate, with the android Ash surreptitiously placed aboard to ensure the safety of any lifeforms that were discovered. Though the Nostromo was damaged while landing on LV-426, a three-man exploration team, consisting of Captain Dallas, First Officer Kane and navigator Lambert, set out on a brief exploration of the moon's surface and discovered a Derelict spacecraft that was responsible for transmitting the signal. While exploring the derelict's interior, the crew came across the fossilized remains of the Engineer pilot and thousands of Xenomorph Eggs stored within the ship's cargo hull. Kane was subsequently impregnated by a Facehugger and was taken back to the Nostromo for treatment. The Nostromo departed soon afterwards, but the Xenomorph implanted in Kane's chest later birthed in space, leading to the Nostromo's destruction.

Following the loss of the Nostromo, the incident was covered up by the Weyland-Yutani personnel involved.[14] This, coupled with the fact the derelict's beacon was later deactivated by the crew of the Anesidora,[15] meant that, in time, LV-426 passed back into obscurity.

Terraforming and colonization

LV-426 was later selected for terraforming and human colonisation. This process began with the establishment of the colony of Hadley's Hope in 2157,[16] with large-scale terraforming efforts beginning two years later[17] with the construction of a number of Atmosphere Processing Plants to make the moon's atmosphere breathable. The early inhabitants of the colony christened the moon Acheron,[3] after one of the rivers that wound through the netherworld (translated as "River of Pain") in ancient Greek mythology.[18]

Despite this human habitation, the colonists remained unaware of the derelict due to a combination of the moon's thick, debris-laden atmosphere shielding it from both visual and satellite detection, and the Ilium mountain range blocking it from the colony's ground scanners.[19] It wasn't for another twenty years that Russ and Anne Jorden, residents of the Hadley's Hope colony, were sent to investigate the derelict on company orders, after its location was deduced from the testimony of Ellen Ripley, the only survivor of the Nostromo, who had just been rescued from deep space. Russ was subsequently impregnated by a Facehugger during his investigation of the ship, sparking a full-scale outbreak at the colony. A Queen established a Hive in the colony's Atmosphere Processor, and the Xenomorphs killed or captured, cocooned and impregnated nearly all of the colonists.

A select few inhabitants managed to escape the incident: two disparate groups of colonists fled in two separate ships. One group escaped aboard the cargo freighter Onager and sought refuge on the nearby LV-223, ironically the same moon where the USCSS Prometheus disappeared in 2093, while a small group of four led by Captain Brackett of Acheron's resident Colonial Marines contingent safely escaped the system in a shuttle.[18] Rebecca Jorden, daughter of Russ and Anne, was the only colonist left alive at Hadley's Hope, managing to evade the Xenomorphs for an extended period of time thanks to her resourcefulness and familiarity with the colony's ventilation network.

A short while after this, a unit of Colonial Marines was dispatched aboard the USS Sulaco to investigate the loss of contact with the colony, accompanied by Ellen Ripley. After several battles with the Xenomorphs that resulted in the deaths of most of the Marines, the creatures' Hive was destroyed when the Atmosphere Processing Plant's reactor exploded. Only Ripley, Rebecca Jorden, Corporal Dwayne Hicks and the android Bishop escaped. Unknown to them, the Hadley's Hope Queen had stowed away on board the Sulaco, but was subsequently ejected into space by Ripley through an airlock.

Exploration by Weyland-Yutani

Despite the explosion on the moon, several Xenomorphs had survived in the ruins of Hadley's Hope, and a second Queen soon emerged. The Queen and her brood were discovered by a Weyland-Yutani team led by Michael Bishop, which had set up the Origin Facility around the derelict to study the Xenomorphs. A second group of Marines, hailing from the USS Sephora, subsequently landed on LV-426 and engaged both the Weyland-Yutani forces and the Aliens. The research facility was overrun, although several personnel, including all the surviving Colonial Marines, managed to escape aboard a Weyland-Yutani starship.

In the early 23rd century, the Derelict's telemetry was traced from LV-426 to LV-1201, where Weyland-Yutani set up a new research facility to study the Xenomorphs.

Behind the scenes


In Alien, LV-426 is not named and is simply referred to as a "planetoid" or "ball". In Aliens, the name LV-426 is given at the inquest aboard Gateway Station and subsequently throughout the film. The novelization of the film additionally states that the moon is also known as Acheron.[3] Director James Cameron also gives the name Acheron in a behind the scenes interview on the production of Aliens, after the river that, in Greek mythology, is described as the "stream of woe", a branch of the river Styx, and which forms the border of Hell in Dante's Inferno. Greek history and mythology are a recurring point of reference in the Alien franchise; other notable examples include the comics Aliens: Rogue and Aliens: Dead Orbit (which contain numerous references), the ships Archimedes and Anesidora, the novels Alien: River of Pain and Alien: Into Charybdis, and references to the Titan Prometheus in both Prometheus Tech and the film Prometheus.

Cameron suggests that the moon may have earned the name Acheron from an early colonist with a literary interest and a sense of irony.[20] On the timeline of the official viral website for Weyland Corp, as part of the promotion for the film Prometheus, the moon's name appears as officially "Acheron LV-426", bringing both of the established names together. The moon was originally going to appear in Prometheus, but ultimately the moon LV-223 was used instead.

The name Acheron is reused in the novelization of Alien3, although it was repeatedly misspelled as "Archeron" in early editions. LV-426 is mentioned again in the musings of Dr. Mason Wren in the novelization of Alien Resurrection, in which the researcher reflects that the loss of the derelict was a great setback. Unlike earlier novels, the moon is once more referred to as LV-426. While never overtly stated in any source, it seems likely that LV-426 is the moon's technical designation, while Acheron is a more common name.


  • The Ilium Range mentioned in Aliens is named for the Latin Ilia (one side of the pelvic bone, groin). The mountain range therefore prophetically symbolises the pelvic shape of the derelict spacecraft (as well as the phallic shape of the Xenomorph cranium).
  • In Alien, the film's original screenplay and its accompanying novelization, LV-426's diameter is said to be only 1,200 km.[1] For a moon so small to have a surface gravity of 0.86 G, it would have to be unfeasibly dense, and its surface would also be visibly curved when standing on it (which it clearly is not in the film). The Colonial Marines Technical Manual later changed the moon's size to a more realistic 12,201 km diameter, however, the Weyland-Yutani Report later reverted this to the original size.
  • In Alien: Descent, LV-178 is erroneously referred to as Acheron and shown as being in the Zeta Reticuli system.




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  2. 2.0 2.1 S. D. Perry. Alien: The Weyland-Yutani Report, p. 84 (2014), Insight Editions.
  3. 3.0 3.1 3.2 Alan Dean Foster. Aliens, p. 36 (2014), Titan Books.
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  12. "Yutani Studio - Quiet Eye Analysis". Retrieved on 2020-07-19.
  13. Alan Dean Foster. Alien, p. 261 (2014), Titan Books.
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