Lift-off of a Titan IV rocket. At the time, it was one of America's largest launch vehicles. It was mainly used for launching heavy military satellites and some deep space missions. It has two solid-fuel boosters strapped onto the side of a liquid-fuel two-stage rocket. At launch, it developed about 16 million newtons of thrust, most of this coming from the strap-on boosters. Titan IV was developed because of the Space Shuttle's inability to lift heavy payloads. It was first launched in June 1989, and it launched for the last time in October 2005.