دلتا 4
The Delta IV Heavy consists of a central Common Booster Core (CBC), with two additional CBCs as LRBs instead of the GEM-60 solid rocket motors used by the Delta IV Medium+ versions. At lift off, all three cores operate at full thrust, and 44 seconds later the center core throttles down to 55% to conserve fuel until booster separation. The Angara A5V and Falcon Heavy are conceptually similar to Delta IV Heavy.