The Future of Earth-to-Orbit Propulsion

by Robert C. Truax Image credit: SpaceX.com The story of turbopump rocket development is an interesting one of trial and error. Many sidelines were explored before the objectives of light weight and high performance were finally attained with the main engines for the Shuttle. Russian rocket development followed a somewhat similar path, and the end result was very similar: a topping cycle with high combustion chamber pressures. But turbopump engines, whether high pressure or low, were a mistake from the very beginning. They simply are not worth what they cost in time and money. In all the early development efforts, pump-fed systems were preceded by a pressure-fed version. In every case, the mission was accomplished and the program goals met before the development of the pump system was completed. After the X-I broke the sound barrier with its pressure-fed rocket engine, who ever heard of the D-558-2-powered by a pump-fed engine? Technically simple two-stage launchers with pressure-f ...