[1] The Common Booster Core was 40.8 metres (134 ft) long, had a diameter of 5.1 metres (17 ft) and was powered by a single RS-68 engine burning liquid hydrogen and liquid oxygen.

[5] The first flight of the Delta IV Heavy, featuring three Common Booster Cores, was conducted on 21 December 2004.

On this flight all three CBCs malfunctioned, cutting off prematurely due to cavitation in their oxidizer lines, and resulting in the rocket reaching a lower orbit than that which had been planned.

In response to the failure, additional pressure valves were installed on future launches.

The CBCs were manufactured in United Launch Alliance's 1,500,000-square-foot (140,000 m2) manufacturing facility in Decatur, Alabama and then transported by the RS RocketShip to either Vandenberg Air Force Base or Cape Canaveral Air Force Station where they were integrated with the spacecraft and other components such as strap-on boosters and a Delta Cryogenic Second Stage.