mass, and in its place, a common bulkhead, similar to that used on both the S-II and S-IVB stages of the Saturn V, would have been used between the tanks. The savings from these changes were used to increase propellant capacity, which was . The spray-on foam insulation was the only part of the Shuttle's ET that would have been used on this new Saturn-derived upper stage. See also Ares IV, a proposed heavy-lift variant of Ares I and V combined. DIRECT, shuttle-derived launcher proposed as alternative to Ares I and Ares V. Liberty (rocket), a proposed medium-lift rocket like the Ares I, a SDLV using an SRB-derivative first stage Omega, ATK's proposed new rocket based on SDLV SRB-derived first and second stages and Aerojet Rocketdyne RL10 third stage List of Constellation missions Boilerplate (spaceflight) References External links NASA Ares I page GAO-08-51, Ares I Report to Congress, GAO Cancelled space launch vehicles Partially reusable space launch vehicles Ares (rocket family) Shuttle-derived space launch vehicles Orion (spacecraft)