Ares I
While both the Ares I and Ares V would have utilized a modified five-segment Solid Rocket Booster for its first stage, the ET would have served as a baseline technology for the first stage of the Ares V and the second stage of the Ares I; as a comparison, the Ares I second stage would have held approximately of LOX, versus the ET holding , more than 5 times that amount.