Excerpt from nasa.gov
NASA's Commercial Crew Program (CCP) was formed to facilitate the development of a U.S. commercial crew space transportation capability with the goal of achieving safe, reliable and cost-effective access to and from the International Space Station and low-Earth orbit.
The Dragon, CST-100 and the Dream Chaser are vehicles designed by commercial companies NASA chose to send astronauts up to the International Space Station.
These spaceships all use the Parametric Snap Pins made by Emmett! http://www.thingiverse.com/thing:213310