The CZ-9 was initially designed as a three-staged rocket, with a first-stage core diameter of 10 meters and using a cluster of four engines. Multiple variants of the rocket have been proposed, with CZ-9 being the largest: this 'base variant' has four additional liquid-fuel boosters strapped onto the core stage (each individual booster would be up to 5 meters in diameter) and it is this variant that has the aforementioned LEO payload capacity of 140,000 kg. In addition to the base variant, there is the CZ-9A variant, which has only two additional boosters and an LEO payload capacity of 100,000 kg. Finally, there is the CZ-9B, having only the bare 10-meter diameter core stage and an LEO payload capacity of 50,000 kg. The expected payload capacities of the Long March 9 place it in the class of the super heavy-lift launch vehicle. The rocket's development program was formally approved by the Chinese government in 2021.
