It's the first time since the retirement of the shuttles nine years ago that an American crew has made the journey from US territory.
Doug Hurley and Bob Behnken are not only trialling a new capsule system, they are also initiating a new business model for Nasa.
The agency will no longer own the vehicles it uses but merely purchase the "taxi" service offered by SpaceX.
It's hoped companies other than tech billionaire Elon Musk's SpaceX outfit will come in to expand the market. The aerospace giant Boeing already has a contract with Nasa to do so.