Musk said the new rocket, which he calls MCT, will be "several times" as powerful as the 1 Merlin series, and won't use Merlin's RP-1 fuel. Beyond adding that it will have "a very big core size", he declined to elaborate, promising more details in "between one and three years".
This seems like a rocket that would be used for launching missions to Mars or large space stationary in one piece or new supersized spy satellitesbor other new space capabilities.
Shotwell said a possible payload range of the new rocket is 150-200t to low Earth orbit (LEO). A vehicle of that size would easily eclipse NASA's proposed Space Launch System, which will eventually be capable of launching 130t to LEO.
Musk declined to say what 'MCT' stands for, and declined to answer further questions on the project.
During an April interview, SpaceX president Gwynne Shotwell discussed a project with similar characteristics, describing engines with "more than 1.5 million pounds" of thrust.
"We've looked at a number of different architectures, we haven't honed in on one just yet," said Shotwell. "I think we're still considering vehicle diameter. But the vehicle diameter is large, 7m minimum, multiple engines. These are big rockets."
She further noted that the company was examining grouping several of the engines together, as SpaceX has done with the current Falcon 9 rocket