Titan is a family of U.S. expendable rockets used between 1959 and 2005. A total of 368 rockets of this family were launched, including all the Project Gemini manned flights of the mid-1960s. Titans were part of the American intercontinental ballistic missile deterrent until the late 1980s, and lifted other American military payloads as well as civilian agency intelligence-gathering satellites. Titans also were used to send highly successful interplanetary scientific probes throughout the Solar System.