"Industry tells us… [they can] make 2019 for an engine, but I must say an engine alone will not get us to space. It needs to be integrated with a rocket, it needs to be tested, it needs to be certified, and to get all of that done, to have a launch capability will be longer than 2019," James said.
The United States currently relies on the Atlas V rocket powered by Russia’s RD-180 engine for its national defense space launches. In 2014, the Congress instituted a law requiring the Pentagon to cut its reliance on the RD-180 after the downturn in US-Russia relations.
Only two families of launch vehicle, the Atlas and the Delta rockets, are able to reach the full range of orbits and carry the heaviest payloads for the United States. In January, the US Air Force awarded contracts to Orbital ATK and SpaceX to develop prototypes of US-built rocket engines to replace the RD-180.