NASA gave the green light Tuesday to a joint US-European rocket project that could carry humans into space aboard commercial crew vehicles. The Liberty rocket, which is being designed by the US aerospace company Alliant Techsystems (ATK) and EADS\' Astrium space division, would carry aloft commercial spacecraft currently being designed by a variety of other companies. NASA, in an agreement announced Tuesday, said it would work with the companies to develop the launch system, helping to review safety requirements, design and other issues. The deal does not come with any NASA funding, according to a report of the German Press Agency \"DPA\".