how do i create a ssto ? is very difficult

@Insanity That sad :(

You cant expect to be able to make ssto's like in KSP because of several reasons. We dont have any high altitude high performance optimized jet engines that can turn into a rocket engine, the planets and therefore the velocities required are much larger and we dont have KSP's nuclear engines, which are unbelievably overpowered, because they use a fuel with densities like kerosene, while having the efficiency of liquid hydrogen.