Terrain & ClimateEdit
Acheron has a 1200 km diameter at its quadrant points QBR 157 052 and has a molten lava base. It's atmosphere is comprised of 10% Argon, 85% Nitrogen and 5% Neon and maintains a gravitational field equivalent to 0.86 of that on Earth.
LV-426 was described as being almost primordial. 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.
In 2122, the commercial tow freighter Nostromo touched down to investigate a mysterious signal on the planetoid per company protocol. Though the Nostromo 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 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 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 soon lifted off again, but the creature implanted an embryo in Kane which birthed from his chest in space, leading to the Nostromo's destruction.
Approximately thirty-seven 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.
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. 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 grew 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 creatures' 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 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, and also in the original screenplay and accompanying novel: while the Aliens: Colonial Marines Technical Manual (a supplementary book to Aliens) gives a figure of 12,201 km. However, the latter is not considered canon since it was simply a book created by a fan.