Delta 4 Heavy uses three of the Delta 4 Common Booster Cores side by side to launch heavy payloads.
The Delta 4 Heavy is one of the most powerful boosters commercially available, with one of the largest operational payloads (until the Falcon 9 Heavy becomes operational).
It uses three CBC boosters, each by itself a Delta 4 first stage powered by RS-68 engines burning LOX/LH2.
