|Country of origin||United States
|Height||90.00 m (300 ft)|
|Diameter||5.40 m (18 ft)|
|Payload to LEO||20,000 kg (44,500 lb)|
|Engines||5-segment Shuttle-derived Solid Rocket Booster|
|Engines||1 × Vulcain 2|
|Specific impulse||431 seconds (vacuum)|
|Burn time||650 seconds|
Liberty was a 2011 launch vehicle concept proposed by Alliant Techsystems (ATK) and 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. It was intended to be launched from Kennedy Space Center.
Liberty was proposed as a vehicle to service the International Space Station for crew and cargo, but its capacities and could potentially have allowed for government and commercial satellite launches, including to Geostationary transfer orbit.
The ATK/Astrium Liberty proposal was not initially selected by NASA in the 2011 contract awards to assist development of a commercial space transportation system to replace the Space Shuttle; however, the team continued development in the hope of gaining funding from NASA in future years. On September 13, 2011, NASA and ATK held a joint news conference to announce they had signed an unfunded Space Act Agreement (SAA) to collaborate on the development of the Liberty Transportation System as part of the agency's Commercial Crew Development Round 2 activities. NASA suggested this agreement could "accelerate the availability of U.S. commercial crew transportation capabilities."
In January 2012 NASA’s Commercial Crew office announced ATK had successfully held a Launch System Initial Systems Design (ISD) Review of the Liberty Transportation System, the third of five milestones to be completed under the SAA. The current SAA continued through at least March 2012.
In May 2012 ATK announced that Liberty will indeed be a complete commercial crew transportation system, including the spacecraft, abort system, launch vehicle, and ground and mission operations. The spacecraft will be narrowly derived from concepts generated during the Orion program and make use of the Orion Service Module. ATK projected that the first launch could have taken place as early as 2013, with astronauts launching by 2015.
Liberty was not among the vehicles selected for funding announced on August 3, 2012 under the Commercial Crew Integrated Capacity program. ATK's stated goal prior to the CCiCAP award announcement was to begin test launches in 2015, with a crewed flight in 2016. In early August 2012, shortly before NASA announced the selectees for CCDev award, ATK Liberty manager Kent Rominger stated that the program would continue even without CCiCAP funding. However, following the NASA decision to not select Liberty as a design for further government funding ATK president and CEO Mark DeYoung stated that the company was "'moving on' after the failure to win a NASA contract reassessing their plans and the decision would not cause any financial hardship."
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