Sir Ridley Scott began plannng a prequel to his 1979 blockbuster hit, Alien even as early as 2000, and discussed the project extensively with James Cameron. Ultimately, though, Alien vs. Predator became the project they worked on, leaving Scott to think more about where he wanted the prequel to go. Many regard Prometheus (2012) as that prequel, but Scott has said that it is not the explicit prequel to Alien, although much of its content is explanatory of the universe in which Alien took place.
Thematically, the film is at least conceptually related to Alien in that both movies deal with the unknown and the preternatural by way of interstellar travel. One key difference between the films is that Prometheus is inherently a story of human origins--almost a fictive religion. This is implied by the title which borrows the name of a Greek Titan who was indicted by Zeus for stealing fire from Mount Olympus and giving it to humankind.
The title Prometheus might also be a reference to Mary Shelley's famous novel, Frankenstein: A Modern Prometheus. There are certainly strong thematic connections between Frankenstein and Scott's first movie, Alien.
The movie was released in June, 2012, almost 33 years after the release of Alien in 1979. The movie's estimated budget was $130 million, and was shot entirely in 3D. But, the movie still grossed a staggering revenue, bringing in $403 M. The film received mixed reviews from critics, some of whom were critical of the plot's alleged lack of focus, but over all, the film was well received by the public.