Delta IV



The Nation’s Heavy Lifter

The Delta IV Heavy rocket was the pinnacle in the Delta family evolution. The Delta IV Heavy rocket was a workhorse for the National Reconnaissance Office (NRO) launching 12 missions delivering critical national security payloads. The heavy-performance rocket is recognized for delivering high-priority missions for national security and NASA's first Orion spacecraft on an uncrewed flight test and sent the Parker Solar Probe to study the atmosphere of the Sun.

The Delta rocket played a pivotal role in the evolution of space flight since the 1960’s. The Delta rocket family had a remarkable success rate over six decades of flights and concluded with 389 launches. The final Delta mission signals ULA’s evolution to the new Vulcan rocket, providing even higher performance than our three-core Delta IV Heavy rocket in a single-core rocket to launch heavy-class missions for the nation. 


The Delta IV launch system was available in three configurations: the Delta IV Medium+, with two or four solid rocket motors (SRMs) and the Delta IV Heavy. Each configuration was comprised of a common booster core (CBC), a cryogenic upper stage and a 5-meter-diameter payload fairing (PLF).

The Delta IV Heavy employed two additional CBCs as liquid rocket boosters to augment the first-stage CBC.



Optimal orbit for each customer, delivered industry best spacecraft orbital insertion accuracy.













1,840 kg

4,060 lbs

5,080 kg

11,200 lbs

11,060 kg

24,380 lbs

9,610 kg

21,180 lbs

10,220 kg

22,530 lbs


2,710 kg

5,970 lbs

6,890 kg

15,190 lbs

13,730 kg

30,250 lbs

11,600 kg

25,580 lbs

12,830 kg

28,270 lbs


6,580 kg

14,500 lbs

14,210 kg

31,330 lbs

28,370 kg

62,540 lbs

23,560 kg

51,950 lbs

25,980 kg

57,280 lbs

GEO (Geosynchronous Orbit)=35,786 km Circular at 0 deg

GTO (Geosynchronous Transfer Orbit)=35,786 km x 185 km at 27.0 deg
LEO (Low Earth Orbit-Reference) =200 km circular at 28.7 deg or 90 deg

LEO ISS (Low Earth Orbit-International Space Station) =407 km circular at 51.6 deg

Payload Fairings

Delta IV offered a 5-meter-diameter PLF, optimized for the configuration and mission need. The Delta IV Medium used a standard carbon composite bisector design. The Delta IV Heavy was available with an elongated carbon-composite bisector or metallic trisector PLF.



Main Engine

Design simplicity and demonstrated capability defined the Delta IV RS-68A main engine. Designed and manufactured by Aerojet Rocketdyne, the throttleable RS-68A engine was the largest existing hydrogen-burning engine. Conceived using a simplified design approach, it had fewer parts, was lower risk and had inherently reliable operation.

  • Nominal Thrust (sea level): 702,000 lbs

  • Specifc Impulse (sea level): 362 seconds

  • Length: 204 in

  • Weight: 14,876 lbs

  • Fuel/Oxidizer: Liquid Hydrogen/Liquid Oxygen

Solid Rocket Motors

For additional thrust at liftoff, the Delta IV Medium+ used either two or four Northrop Grumman solid rocket motors (SRMs). The SRMs were strapped to the common booster core and jettisoned in-flight for maximum performance.

  • Peak Vacuum Thrust: 280,000 lbf

  • Specific Impulse: 275.2 seconds

  • Length: 636 in

  • Weight: 74,500 lbs

  • Nominal Burn Time: 90 seconds

Upper Stage

The Delta IV relied on the RL10 propulsion system to power the second stages. Logging an impressive record of nearly 400 successful flights and nearly 700 firings in space, RL10 engines, manufactured by Aerojet Rocketdyne, harnessed the power of high-energy liquid hydrogen. The RL10 boasted a precision control system and restart capability to accurately place payloads into orbit.

The Delta IV employed the RL10B with the world’s largest carbon-carbon extendible nozzle for increased performance.

  • Nominal Thrust: 24,750 lbs

  • Specifc Impulse: 465.5 seconds

  • Fuel/Oxidizer: Liquid Hydrogen/Liquid Oxygen

  • Length: 86.5 in (stowed); 163.5 in (deployed)

  • Diameter (nozzle extension): 84.5 in

  • Weight: 664 lbs


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