Ellen Louise Ripley is a fictional character and the original protagonist of the Alien film series, played by American actress Sigourney Weaver. Considered one of the greatest characters in science fiction film history, the character earned Weaver worldwide recognition, and remains her most famous role to date. Although she was originally conceived as male for the first Alien film (in which the character is only known as Ripley), director Ridley Scott decided early in production to make her a woman.
Alien (1979) and its sequel Aliens (1986) were heralded for challenging gender roles, particularly in the science fiction, action, and horror genres. Weaver's performances are also highly praised: for Aliens, she earned her first Academy Award nomination for Best Actress, which is now seen as a landmark since the Academy, to that point, had given little recognition to the genres of science-fiction and horror. For her role in the franchise, Weaver has also been nominated for a Golden Globe Award for Best Actress in a Motion Picture Drama, a BAFTA Award for Best Leading Newcomer, and four Saturn Awards for Best Actress, winning one for Aliens.
Ripley is often considered one of the most significant female protagonists in cinematic history, and is a prominent figure in popular culture. Today, Ripley's influence extends beyond that of the original film franchise; she has appeared in novels, comic books and video games.
Source : Wikipedia
