Before Alien, science fiction space movies had a certain look — all shiny and pristine. Think of the corridors of the Starship Enterprise. The future is clean and bright, apparently. But would it really look like that? I doubt it. Alien was the first movie set on a spaceship that looked lived in.

The Nostromo is a space tug boat. Its crew are not military, they work for a commercial mining operation. There are seven crew members on Nostromo: Captain Dallas (Tom Skerritt), Executive Officer Kane (John Hurt), Warrant Officer Ripley (Sigourney Weaver), Science Officer Ash (Ian Holm), Navigator Lambert (Veronica Cartwright), Chief Engineer Parker (Yaphet Kotto), and Engineering Technician Brett (Harry Dean Stanton). Plus the ship’s cat, Jonesy. The ship is run by an AI called “Mother”.

On their way home, Mother wakes the crew up from cryo-sleep early to investigate a signal beacon from an unknown planet. Dallas, Kane and Lambert leave the ship to investigate and discover a derelict alien ship with a dead alien pilot. While looking around, Kane discovers a bunch of large, leathery egg-like sacks. One of them opens and a spindly creature jumps out of it and attaches itself to Kane’s face. It eats right through his space helmet.

When Kane’s crewmates bring him back to the ship, Ripley follows protocol and refuses to let them out of quarantine. But Ash ignores Ripley and opens the door. The thing on Kane’s face has a long tail that it wraps around his neck. Any attempt to remove it causes it to tighten its grip, threatening strangulation. So they leave Kane in sickbay until some hours later when the facehugger falls off of Kane’s face, apparently dead. Kane wakes up and seems no worse for wear. Until dinnertime. Unless you grew up in a cave, you know what happens next. The notorious dinner scene has been spoofed by everyone from Mel Brooks to the Muppets.

The ‘chestburster’ skitters away before the crew can react. The rest of the movie is about their attempts to purge the alien threat and stay alive.

It isn’t just the grimy verisimilitude that makes this movie perfect. It also gave us the most badass movie heroine in Hollywood history. Alien came out in 1979. Women couldn’t even open their own bank accounts until 1974. The screenplay did not identify any of the characters by gender. It was producer Alan Ladd Jr. who suggested making Ripley a woman. She ended up being the last character cast. Meryl Streep was Ridley Scott’s first choice, but it was right after John Cazale died (Streep’s boyfriend). Helen Mirren, Genevieve Bujold and Katherine Ross were also in the mix. Weaver was a stage actress who had never done a film before. She was the perfect choice.

There are a lot of ways that Alien could have gone wrong. It was almost a B movie produced by Roger Corman. Fox only got interested after the phenomenal success of Star Wars. They were desperate to put out another space movie and the only space script they had was Alien. The studio didn’t like H.R. Giger’s Alien design, one of the most striking features of the film. That was a hill Ridley Scott was willing to die on so Giger’s designs stayed in.

There is a director’s cut of Alien that adds one major scene, trims a lot of other scenes, and rearranges the edit so it doesn’t appear that Ripley risked her life for the cat. I prefer the director’s cut but your mileage may vary.