When Falcon Heavy lifts off, it will be the most powerful operational 
rocket in the world by a factor of two. With the ability to lift into 
orbit nearly 64 metric tons (141,000 lb)---a mass greater than a 737 
jetliner loaded with passengers, crew, luggage and fuel--Falcon Heavy 
can lift more than twice the payload of the next closest operational 
vehicle, the Delta IV Heavy, at one-third the cost. Falcon Heavy draws 
upon the proven heritage and reliability of Falcon 9. 

Its first stage is composed of three Falcon 9 nine-engine cores whose 27
 Merlin engines together generate more than 5 million pounds of thrust 
at liftoff, equal to approximately eighteen 747 aircraft. Only the 
Saturn V moon rocket, last flown in 1973, delivered more payload to 
orbit. Falcon Heavy was designed from the outset to carry humans into 
space and restores the possibility of flying missions with crew to the 
Moon or Mars.