Delta IV Heavy

The Delta IV Heavy consists of a central Common Booster Core (CBC), with two additional CBCs as liquid rocket boosters instead of the GEM-60 solid rocket motors used by the Delta IV Medium+ versions. Each CBC uses a single RS-68 engine. The Delta IV Heavy uses the same Delta Cryogenic Second Stage (DCSS) as the Delta IV Medium+ rockets. The rocket is currently being phased out in favor of United Launch Alliance's Vulcan rocket, which offers more competitive pricing for the same capability.