Alien came out on May 25th, 1979, 2 years to the day after Star Wars: A New Hope hit theatres. You couldn't create two more different visions of space if you tried.
Alien depicts a future with space travel that's gritty, dark and realistic. These space travelers aren't heroes; they're blue collar workers just trying to do their jobs. Which makes the attack by an acid-blooded alien that much more terrifying.
The ship, the Nostromo looks like what it is: an oil rig in space. It looks incredibly realistic, especially for when it was made. Sure, they control the ship using outdated CRT monitors, but Ridley Scott was clearly influenced by Stanley Kubrick's realism in 2001. He just added pants-shitting terror to that realism.
And while both sci-fi franchises have pumped out regrettable sequels since the originals hit, both have had a huge influence on sci-fi movies since then. Star Wars may have redefined all movies set in space, but it took Alien to make space so goddamned scary.
Gizmodo '79 is a week-long celebration of gadgets and geekdom 30 years ago, as the analogue age gave way to the digital, and most of our favourite toys were just being born.