We are living in a golden age of rockets, as private companies like SpaceX, Blue Origin, and Virgin Galactic experiment with new rocket bodies for astronomic deliveries. Yet this golden age is built on the bones of a previous era of spacecraft hurling. Or at least, if not the bones, the rocket engines.

United Launch Alliance, a joint venture between defense giants Lockheed Martin and Boeing, has for years delivered military satellites into space using rockets powered by old Russian engines. With Russian spare parts no longer politically viable, ULA's looking for a new rocket engine, and on Monday, the Air Force announced a big investment to help Aerojet Rocketdyne create one.

Political Turmoil

ULA uses Atlas V rockets, designed with Russian-built RD-180 engines in the first stage.