low-Earth orbit in preparation for transit for missions beyond low-Earth orbit. (B) The capability to carry an integrated upper Earth departure stage bringing the total lift capability of the Space Launch System to 130 tons or more. (C) The capability to lift the multipurpose crew vehicle. (D) The capability to serve as a backup system for supplying and supporting International Space Station cargo delivery requirements or crew delivery requirements not otherwise met by available commercial or partner-supplied vehicles. (E) The capacity for efficient and timely evolution, including the incorporation of new technologies, competition of sub-elements, and commercial operations. (2) Flexibility The Space Launch System shall be designed from inception as a fully integrated vehicle capable of carrying a total payload of 130 tons or more into low-Earth orbit in preparation for transit for missions beyond low-Earth orbit. The Space Launch System shall, to the extent practicable, incorporate capabilities for evolutionary growth to carry heavier payloads. Developmental work and testing of the core elements and the upper stage should proceed in parallel subject to appropriations. Priority should be placed on the core elements with the goal for operational capability for the core elements not later than December 31, 2016. (3) Transition needs The Administrator shall ensure that critical skills and capabilities are retained, modified, and developed, as appropriate, in areas relating to solid and liquid engines, large diameter fuel tanks, rocket propulsion, and other ground test capabilities for an effective transition to the follow-on Space Launch System. 71522. Multipurpose crew vehicle (a) Initiation of Development (1) In general The Administrator shall continue the development of a multipurpose crew vehicle to be available as soon as practicable, and no later than for use with the Space Launch System. The vehicle shall continue to advance development of the human safety features, designs, and systems in the Orion project.