Liberty (rocket)
Liberty was a 2011 launch vehicle concept proposed by ATK (now part of Northrop Grumman Space Systems via the acquisition of Orbital ATK) and Airbus Defence and Space (formerly Astrium) for phase 2 of the NASA Commercial Crew Development (CCDev) program intended to stimulate development of privately operated crew vehicles to low Earth orbit. Similar to the defunct Ares I project, which consisted of a five segment Space Shuttle Solid Rocket Booster (SRB) and a new cryogenic second stage, Liberty would combine a five-segment SRB with the core stage of the European Ariane 5 as a second stage.