Now, as lawmakers consider a total reorganization of the US military's space operations, the Pentagon's latest attempt to purchase new launch vehicles has become a hotly contested rivalry featuring the military-industrial complex and rocket billionaires Elon Musk and Jeff Bezos. Of course, there's a Russia angle, too.

The battle could shape not just US national security but also the future of private space companies writ large—access to revenue from military launches bolster a rocket-maker's offerings to a range of potential customers. Musk's SpaceX revolutionized the space industry and became the world's leading commercial launcher thanks, in part, to winning Pentagon business.