We conduct a comparative analysis of cost indexes for launch vehicle with the expendable and reusable lower stage. The obtained relations connect the cost of launch with the costs of the rocket core construction, propulsion system and control system, recovery of the lower stage and the multiplicity of its use. The cost of the launch depending on the multiplicity of utilizing the lower stage was estimated for a model launch vehicle.

             We give also a qualitative analysis of the assumptions applied in these calculations. It is shown that for each combination of the cost of rocket components and expenses for recovery of the lower stage, there is an optimal multiplicity of its use. Further increase in the multiplicity of its launch does not show a significant economic effect in terms of reducing the cost of the launch, but increases one-time expenses for the development and working out of reusable components.