The Titan II was an American Human-rated expendable rocket that was in service with NASA and the United States Air Force in the mid-20th century. The rocket was used for national defense and space exploration. Titan II rockets were later used in the mid-21st century, during World War III, as a type of nuclear missile. One of this type of rocket formed the framework and launch vehicle for Zefram Cochrane's experimental warp ship, the Phoenix. (Star Trek: First Contact)