Senate authorizers want the Air Force to explore the feasibility of using foreign allied launch vehicles to lift some national security space payloads should the service be unable to use United Launch Alliance's Atlas V rocket. Congress in fiscal year 2015 called on the service to end its reliance on the Russian-made RD-180 engine that powers ULA's Atlas V by 2019, and some lawmakers are concerned the service is dragging its feet in meeting that requirement. Senate Armed Services Committee...