The Alien, specifically the Xenomorph, got onto the Nostromo spaceship in Alien (1979) because the crew unknowingly brought it aboard after investigating a distress signal on an uncharted planetoid.
The sequence of events leading to the creature's infiltration of the Nostromo began when the commercial towing vehicle, on its return journey to Earth, intercepted a mysterious transmission.
The Distress Signal and Discovery
While rerouting to investigate a strange signal emanating from a desolate planetoid, later identified as LV-426 (also known as Acheron), the crew of the Nostromo inadvertently set in motion the events that would bring the deadly extraterrestrial organism onto their vessel.
Upon landing on the treacherous terrain of LV-426, an away team consisting of Captain Dallas, Executive Officer Kane, and Navigator Lambert was dispatched to locate the source of the signal. They discovered a massive, horseshoe-shaped derelict spacecraft of non-human origin.
- Investigation: Following the signal into the derelict, Kane ventured into a vast chamber filled with thousands of leathery, egg-like objects.
- The Attack: As Kane peered into one of the eggs, a creature known as a facehugger burst forth, attaching itself firmly to his face.
Boarding the Nostromo
Despite the strict quarantine protocols emphasized by Warrant Officer Ripley, Captain Dallas made the critical decision to bring the incapacitated Kane, with the parasitic facehugger still clinging to him, back aboard the Nostromo for medical examination. This act allowed the Alien lifeform to bypass the ship's defenses.
The table below outlines the critical stages of the Alien's boarding:
| Event | Location | Key Personnel Involved | Outcome |
|---|---|---|---|
| Distress Signal Detection | Deep Space | All Crew | Diversion to LV-426 |
| Derelict Discovery | Planet LV-426 | Dallas, Kane, Lambert | Uncovering alien spacecraft |
| Facehugger Attack | Derelict Spaceship | Kane | Kane incapacitated, organism attached |
| Return to Nostromo | Nostromo Airlock | Dallas, Ripley (opposed) | Alien host brought onboard |
| Chestburster Emergence | Nostromo Mess Hall | Kane (victim) | Birth of the Xenomorph, Kane's death |
Emergence and Infiltration
After a period of incubation, the facehugger detached from Kane's face and seemingly died. However, the true terror emerged later during a communal meal. A small, serpent-like creature, subsequently dubbed a chestburster, violently erupted from Kane's chest, killing him instantly, and quickly scurried away into the ship's ventilation system. This creature rapidly grew into the full-sized, terrifying Xenomorph that would systematically hunt down the remaining crew members.
The Alien's presence on the Nostromo was therefore a direct consequence of the crew's encounter with the mysterious signal and their subsequent decision to bring an infected crew member back onto their vessel.
