Boeing and Lockheed are major players, and you're right about the rivalry, but they're not the only ones. ATK (the former Thiokol) is a major player in the Spa

Boeing and Lockheed are major players, and you're right about the rivalry, but they're not the only ones. ATK (the former Thiokol) is a major player in the Space Launch System project, and politically very well connected; there are also smaller fry like SpaceX and Orbital Sciences (makers of the Pegasus air-launched rocket, and the other commercial supplier for ISS cargo resupply).