Titan IV
Titan IV was an extended length Titan III with solid rocket boosters on its sides. The Titan IV could be launched with a Centaur upper stage, the USAF Inertial Upper Stage (IUS), or no upper stage at all. This rocket was used almost exclusively to launch US military or Central Intelligence Agency payloads. However, it was also used for a purely scientific purpose to launch the NASA–ESA Cassini / Huygens space probe to Saturn in 1997. The primary intelligence agency that needed the Titan IV's launch capabilities was the National Reconnaissance Office (NRO).
Missions: 39
Successes: 35
Partial Failures: 0
Failures: 4
Success Streak: 12
Success Rate: 89.7%