Elon Musk and Spacex had mentioned plans for BFR (Big F**ing Rocket) and the Merlin 2 rocket engine back in 2005. Now there are details of the designs for the Merlin 2 and the Falcon X, Falcon X heavy and Falcon XX rockets.
* Falcon 9 with one successful trial launches 10 tons into orbit.
* A planned “Falcon 9 Heavy” will launch 30 tons
* Falcon X will launch 38 tons into orbit
* Falcon X Heavy 125 tons
* Falcon XX for up to 140 tons but no engine out ability to carry on mission with one engine out.
* Spacex has plans for interplanetary flight
* SpaceX thinks early unmanned cargo missions might best be carried out using “Hall thrusters” (highly efficient ion drive)
* SpaceX considers that a “nuclear thermal” rocket, able to deliver much higher thrust-to-weight ratio and thus shorter journey time than solar/ion engines, is the answer for manned ships.
* a piloted mission to Mars by 2020-2025 can be accomplished if we start building and testing hardware now
* SpaceX’s long-discussed Merlin 2 Lox/rocket propellant-fueled engine, capable of a projected 1.7 million lb. of thrust at sea level and 1.92 million lb. in a vacuum
* Spacex plans a larger Raptor engine