Since the Titan I was a multi-stage Intercontinental Ballistic Missile (ICBM), the vehicle was made up of parts (stages)that separated from the rest of the body once its engines ran out of fuel. This decrease in weight during the flight gave Titan I the ability to have a longer target range and carrier a heavier payload (warhead).
The first stage was powered by two Aerojet Lr87-AJ-3 rocket engines at liftoff that delivered 300,000 pounds of thrust and burned for 134 seconds. When the first stage disconnected, a single Aerojet LR91-AJ-3 rocket engine ignited to power the second stage. Displayed here,, this engine produced 80,000 pounds of thrust and burned for 156 seconds to boost the missile. After the second stage fell away, two small vernier engines made final corrections to it trajectory before burning out. The re-entry vehicle caring the warhead reached an altitude of 541 miles above the Earth's surface (its apogee) before falling to its target.
The engines were fueled by liquid oxygen (LOX) and kerosene (RP-I), but these propellants were dangerous and difficult to handle. LOX had to be kept refrigerated at an extremely low temperature (-195* C) until a Titan I was ordered to launch.
Since both the LOX and RP-I could not be pumped aboard the missile until right before launch, the reaction time from the launch command
to actual liftoff took twenty minutes.