Musk has indicated that SpaceX would reveal the design for a Mars Colonial Transport Rocket by the end of the year. SpaceX began development of the rocket engines before 2014, but the MCT will not be operational earlier than the mid-2020s.
Musk stated that Mars Colonial Transport will be capable of taking 100 people at a time to Mars. Also, SpaceX engine development head Tom Mueller said SpaceX would use nine Raptor engines on a single rocket, similar to the use of nine Merlin engines on each Falcon 9 booster core. He said "It’s going to put over 100 tons of cargo on Mars." The large rocket core that will be used for the booster to be used with MCT will be 10 meters (33 ft) in diameter, nearly three times the diameter and over seven times the cross-sectional area of the Falcon 9 booster cores.
The super-heavy lift launch vehicle for MCT will lift the 100 tonnes (220,000 lb)+ payload of the MCT into orbit and is intended to be fully-reusable. The rocket has not yet been named by SpaceX. The MCT launch vehicle will be powered by the Raptor bipropellant liquid rocket engine.
Musk described his vision for the future of space travel:
“The key is that we have to make the Mars thing work. If we’re going to have any chance of sending stuff to other star systems, we need to be laser-focused on becoming a multi-planet civilization. That’s the next step.”