Blue Origin is developing a relatively secret crew transportation system to be launched initially on an Atlas V launch vehicle, although it is also developing its own reusable launch system.
This proposal was based upon utilizing a modified first stage of the Ariane V as a new second stage, with a Shuttle solid rocket motor as the first stage. Ariane V was to have been the launch vehicle for the canceled European Hermes minishuttle. This new design of launch vehicle has been named “Liberty” and would be used to launch a composite crew capsule.
Sierra Nevada Corporation
Sierra Nevada is developing a small lifting body-style crew vehicle called Dream Chaser also for launch on an Atlas V. This fourth-generation design of lifting body is based upon the NASA HL-20 design and is a fully reusable pressurized lifting body spacecraft. Capable of landing on a conventional runway, this design offers cross-range capability and reduced g-forces on descending occupants and payloads.