Delta IV Heavy

The Delta IV Heavy (Delta 9250H) is an expendable heavy-lift launch vehicle, the largest type of the Delta IV family and the world's second highest-capacity rocket in operation.[4][5] It is manufactured by United Launch Alliance and was first launched in 2004.[6]

Delta IV Heavy
Delta IV Heavy launches from Vandenberg AFB
FunctionOrbital heavy-lift launch vehicle
ManufacturerUnited Launch Alliance
Country of originUnited States
Cost per launch$350 million[1]
Cost per year2018
Height72 m (236 ft)
Diameter5 m (16 ft)
Width15 m (49 ft)
Mass733,000 kg (1,616,000 lb)
Payload to LEO28,790 kg (63,470 lb)
Payload to GTO14,220 kg (31,350 lb)
Associated rockets
FamilyDelta IV
Launch history
Launch sites
Total launches10
Partial failures1
First flight21 December 2004 (USA-181)
Last flight19 January 2019 (NROL-71)
Notable payloads
Boosters (CBC)
No. boosters2
Length40.8 m (134 ft)
Diameter5.1 m (17 ft)
Empty mass26,000 kg (57,000 lb)
Gross mass226,400 kg (499,100 lb)
Propellant mass200,400 kg (441,800 lb)[2]
Engines1 RS-68A
Thrust3,140 kN (710,000 lbf)
Total thrust6,280 kN (1,410,000 lbf)
Specific impulseSea level: 360 s (3.5 km/s)
Vacuum: 412 s (4.04 km/s)
Burn time242 seconds[3]
FuelLH2 / LOX
First stage (CBC)
Length40.8 m (134 ft)
Diameter5.1 m (17 ft)
Gross mass226,400 kg (499,100 lb)
Propellant mass200,400 kg (441,800 lb)
Engines1 RS-68A
Thrust3,140 kN (710,000 lbf)
Specific impulseSea level: 360 s (3.5 km/s)
Vacuum: 412 s (4.04 km/s)
Burn time328 seconds
FuelLH2 / LOX
Second stage (DCSS)
Length13.7 m (45 ft)
Diameter5.1 m (17 ft)
Gross mass30,700 kg (67,700 lb)
Propellant mass27,220 kg (60,010 lb)
Engines1 RL10-B-2
Thrust110 kN (25,000 lbf)
Specific impulse462 s (4.53 km/s)
Burn time1,125 seconds
FuelLH2 / LOX

The Delta IV Heavy consists 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. 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 boosters burn out at 242 seconds after launch and are separated as the core booster throttles back up to full thrust. The core burns out 86 seconds later, and the second stage completes the ascent to orbit.[3]


The Delta IV line of rockets was developed by McDonnell Douglas, later United Launch Alliance. The Delta IV Heavy is the most powerful member of the line, which also includes the smaller Delta IV Medium.[7] The Delta IV Heavy can lift 28,370 kg (62,540 lbs) to low earth orbit and 13,810 kg (30,440 lbs) to geostationary transfer orbit.[7] It is an all liquid-fueled rocket, consisting of an upper stage, one main booster and two strap-on boosters.[7]

The first launch of the Delta IV Heavy in 2004 carried a boilerplate payload and failed to reach intended orbit. Cavitation in the liquid-oxygen propellant lines caused shutdown of both boosters eight seconds early, and the core engine nine seconds early; this resulted in a lower staging velocity for which the second stage was unable to compensate. The payload was left in a lower than intended orbit.[8] Its first operational payload was the DSP-23 satellite, successfully launched in 2007; it was then used to launch a further five visual and electronic reconnaissance satellites for the National Reconnaissance Office through 2013.

In December 2014, the Delta IV Heavy was used to launch an uncrewed test flight of the Orion Multi-Purpose Crew Vehicle, designated EFT-1. After several delays on December 4,[9] the mission was successfully launched at 12:05 UTC on December 5.[10]


Capacity of the Delta IV Heavy:

The Delta IV Heavy's total mass at launch is approximately 733,000 kg (1,616,000 lb).

Launch history

DatePayload[14]MassLaunch siteOutcome[14]
Dec. 21, 2004DemoSat, Sparkie / 3CS-1 and Ralphie / 3CS-2~6000 kgCape Canaveral[lower-alpha 1]Partial failure[lower-alpha 2]
Nov. 11, 2007DSP-23 Defense Support Program5,250 kgCape Canaveral[lower-alpha 1]Success
Jan. 18, 2009Orion 6 / Mentor 4 (USA-202 / NROL-26)ClassifiedCape Canaveral[lower-alpha 1]Success
Nov. 21, 2010Orion 7 / Mentor 5 (USA-223 / NROL-32)ClassifiedCape Canaveral[lower-alpha 1]Success
Jan. 20, 2011KH-11 Kennen 15 (USA-224 / NROL-49)<17,000 kgVandenberg[lower-alpha 3]Success
June 29, 2012Orion 8 / Mentor 6 (USA-237 / NROL-15)ClassifiedCape Canaveral[lower-alpha 1]Success
Aug. 28, 2013KH-11 Kennen 16 (USA-245 / NROL-65)<17,000 kgVandenberg[lower-alpha 3]Success
Dec. 05, 2014Orion capsule Exploration Flight Test 1 (EFT-1)~21,000 kg[15][lower-alpha 4]Cape Canaveral[lower-alpha 1]Success
June 11, 2016Orion 9 / Mentor 7 (USA-268 / NROL-37)ClassifiedCape Canaveral[lower-alpha 1]Success
August 12, 2018Parker Solar Probe[lower-alpha 5]685 kgCape Canaveral[lower-alpha 1]Success
January 19, 2019NROL-71ClassifiedVandenberg[lower-alpha 3]Success
  1. Launched from Cape Canaveral, SLC-37B
  2. CBCs underperformed, lower orbit than planned
  3. Launched from Vandenberg, SLC-6
  4. The officially reported mass of 21,000 kg includes the Launch Abort System (LAS) which did not reach orbit, but excludes the residual mass of the upper stage, which did reach orbit, likely offsetting the mass of the LAS.
  5. Star 48BV upper stage

Upcoming launches

The following missions have been announced by the National Reconnaissance Office.[16] [17] As of August 2019 these are the final five missions.[18]

Date (UTC)PayloadClient[14]Launch site
Jun 2020NROL-44NROCape Canaveral SLC-37B
Sep 2020NROL-82NROVandenberg SLC-6
H2 2022NROL-91NROVandenberg SLC-6
H2 2022NROL-70NROCape Canaveral SLC-37B
H2 2023NROL-68NROCape Canaveral SLC-37B

Comparable vehicles



Retired or cancelled:

See also


  1. "ULA CEO Tory Bruno". Twitter. Retrieved 12 February 2018. Delta IV Heavy goes for about $350M. That’s current and future, after the retirement of both Delta IV Medium and Delta II.
  2. "Delta IV Heavy". Spaceflight 101. Retrieved July 26, 2014.
  3. "Delta IV Payload Planner's Guide, June 2013" (PDF). United Launch Alliance. Archived from the original (PDF) on July 10, 2014. Retrieved July 26, 2014.
  4. "Mission Status Center". SpaceflightNow. Retrieved July 26, 2014. The ULA Delta 4-Heavy is currently the world’s largest rocket, providing the nation with reliable, proven, heavy lift capability for our country's national security payloads from both the east and west coasts.
  5. "Falcon Heavy, SpaceX's Big New Rocket, Succeeds in Its First Test Launch". NYTimes. Retrieved Feb 6, 2018. The Falcon Heavy is capable of lifting 140,000 pounds to low-Earth orbit, more than any other rocket today.
  6. "Boeing Delta IV Heavy Achieves Major Test Objectives in First Flight" Archived 2012-04-19 at the Wayback Machine, Boeing, 2004, accessed March 22, 2012.
  7. "Delta IV Heavy: Powerful Launch Vehicle". Retrieved 2018-07-21.
  8. "Delta 4-Heavy investigation identifies rocket's problem". Spaceflight Now. Retrieved July 26, 2014.
  9. Bergin, Chris (2012-01-18). "EFT-1 set to receive Spring, 2014 launch date after contract negotiations". Retrieved 21 July 2012.
  10. "Second Stage Ignites as First Stage Falls Away".
  11. "Delta IV Launch Services User's Guide" (PDF). United Launch Alliance. 2013-10-14. pp. 2–10, 5–3. Archived from the original (PDF) on October 14, 2013.
  12. "Delta IV Data Sheet". Space Launch Report. Retrieved July 26, 2014.
  13. Ray, Justin (December 7, 2004). "The Heavy: Triple-sized Delta 4 rocket to debut". Spaceflight Now. Archived from the original on December 11, 2004. Retrieved May 13, 2014.
  14. Krebs, Gunter. "Delta-4". Gunter's Space Page. Retrieved 15 March 2018.
  15. "NASA Orion Exploration Flight Test-1 PRESS KIT" (PDF). NASA. December 2014. p. 12.
  16. Ray, Justin (June 7, 2016). "Surveillance satellite launching Thursday atop Delta 4-Heavy rocket". Spaceflight Now.
  18. Henry, Caleb (21 August 2019). "ULA's Delta 4 Heavy down to final five missions". SpaceNews.
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