The Common Core Booster (CCB) is a rocket stage, which is used as the first stage of the American Atlas V rocket as part of its modular design.

It was also intended that two additional CCBs would be used as boosters on the Atlas V Heavy, however this configuration has not been developed.

Use of a Common Core Booster as the first stage of the Japanese GX was also planned; however, this program was cancelled in late 2009.

[2] Testing of the CCB and its RD-180 engines was conducted in the United States at the Marshall Space Flight Center, and in Khimki, Russia.

[4] As of November 2020, the Atlas V has made 86 flights, all of which have used a single Common Core Booster.