Bethesda games are always jam-packed with content. The Fallout series especially is renowned for holding way, way more Easter eggs and references than anyone could ever find. Remember Uncle Leo the Buddhist Super Mutant?
An Imgur user who goes by 1Times has found several a great reference to the Alien and Prometheus films in Fallout 4. It’s a little bit of a nerdy stretch, but then, all the greatest Easter eggs are.
In a seemingly random spot in the wastelands of Commonwealth, you’ll find a junk item simply called “flux sensor.” It doesn’t do anything for you, but inspecting the item in your inventory will yield a serial number of CM-88B 180924609. A little Googling reveals that this is none of other than the registration number of the USCSS Nostromo, the ill-fated ship crewed by Ripley in the first Alien film.
Is this a crossover? Did Ripley crash-land on a blasted Earth in her past and our future? It doesn’t really jibe with the timeline of either franchise. Unless Doctor Who was involved. Or they got straight up Event Horizon’ed. Probably not, but who knows?
If you’d like to see the flux sensor for yourself, 1Times has placed pictures and a guide on his Imgur page at http://imgur.com/gallery/9Qxkl.