Reports on Thursday night state that Dan O'Bannon passed way at the age of 63. Harry Knowles at Ain't It Cool News broke the story after a phone call from David Fein, producer of the "Alien Legacy" DVD set.
O'Bannon's death has not been confirmed by official sources at this time, but according to the AICN report, O'Bannon had been hospitalized for some time.
Dan O'Bannon co-wrote Alien (1979) with Ronald Shusett, leaving an indelible mark on science fiction cinema. O'Bannon's mark is all over science fiction films since the early 1970s, beginning with his first film in 1974, Dark Star. He also wrote Blue Thunder (1983), Lifeforce (1985), Screamers (1995), and the "Soft Landing" segment of Heavy Metal (1981), and adapted the Philip K. Dick short story "We Can Remember It For You Wholesale" into Total Recall (1990).
O'Bannon was more than just a writer. On Dark Star he was both writer, editor, and actor. He worked as a computer animator on Star Wars. He was even hired to supervise special effects on Alejandro Jodorowsky's failed production of Frank Herbert's Dune. In 1985, he directed Return of the Living Dead.
O'Bannon's next project was slated to be Silvaticus 3015, but according to a Quiet Earth from 2008, the script had not been written and there were no plans for production. The story was reported to center around the near extinction of the human race in 2585 by "mass murder." Another project showing as in development is called "They Bite."
In writing this, seeing how many classic science fiction films he wrote, it's hard to imagine him not writing more for us. He will be missed.