Ares V
Also introduced in 2005, was a heavy-lift Cargo Launch Vehicle (CaLV) named Ares V. Early designs of the Ares V utilized "5" standard-production SSMEs and a pair of 5-segment boosters identical to those proposed for the Shuttle, while later plans redesigned the boosters around the RS-68 rocket engine used on the Delta IV EELV system. Initially, NASA switched over to a system using the 5-segment boosters and a cluster of 5 RS-68s (which resulted in a widening of the Ares V core unit), then NASA reconfigured the vehicle with 6 RS-68B engines, with the boosters themselves becoming 5.5-segment boosters, with an additional half-segment to provide additional thrust at liftoff.