sentences:  In May 2011, the NDS critical design review was completed and qualification was expected to be completed by late 2013.In April 2012, NASA funded a study to determine if a less complex docking system could be used as the NASA Docking System that both met the international community's desire for a narrower soft capture system ring width, as well as providing the ISS a simpler active docking system compared to the then-planned design.Boeing's proposal was the Soft Impact Mating and Attenuation Concept (SIMAC), a design originally conceived in 2003 for the Orbital Space Plane (OSP) Program.