[9][10] The Delta IV Heavy first stage consisted 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.

[13] The first launch of the Delta IV Heavy on 21 December 2004 carried a boilerplate payload and was a partial failure.

[15] On 12 August 2018, the Delta IV Heavy with an additional Star 48BV third stage was used to launch the Parker Solar Probe into an elliptical heliocentric orbit.

[18] Delta IV's final flight was initially scheduled for March 29, 2024 for the National Reconnaissance Office;[19][20] its actual launch date was April 9, 2024 after a postponement.

[21][18][22] Capacity of the Delta IV Heavy: The Delta IV Heavy's total mass at launch was approximately 733,000 kg (1,616,000 lb) and produce around 952,000 kg (2,099,000 lb) of thrust to power the rocket skyward at liftoff.