Delta IV Heavy

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Delta IV Heavy
NROL-71 Wide (cropped alt).jpg
Delta IV Heavy launches from Vandenberg
FunctionOrbital heavy-lift launch vehicle
ManufacturerUnited Launch Alliance
Country of originUnited States
Cost per launchUS$350 million [1]
NRO: US$440 million
Cost per year2018
Height72 m (236 ft)
Diameter5 m (16 ft)
Width15 m (49 ft)
Mass733,000 kg (1,616,000 lb)
Payload to LEO
Mass28,790 kg (63,470 lb)
Payload to GTO
Mass14,220 kg (31,350 lb)
Associated rockets
FamilyDelta IV
Launch history
Launch sites
Total launches11
Partial failure(s)1
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 time1125 seconds
FuelLH2 / LOX

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, behind SpaceX's Falcon Heavy rocket.[4][5] It is manufactured by United Launch Alliance and was first launched in 2004.[6]

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 rocket uses three RS-68 engines, one in the central core and one in each booster.[7]


Delta IV Heavy for Exploration Flight Test-1 (EFT-1), in 2014.

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.[8] 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.[8] It is an all liquid-fueled rocket, consisting of an upper stage, one main booster and two strap-on boosters.[8]

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.[9] 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 spacecraft, designated Exploration Flight Test 1 (EFT-1). After several delays, the mission was successfully launched at 12:05 UTC on 5 December 2014.[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) and produce around 952,000 kg (2,099,000 lb) of thrust to power the rocket skyward at liftoff.[14]

Launch history[edit]

Flight No. Date Payload [15] Mass Launch site Outcome [15]
1 21 December 2004 DemoSat, Sparkie / 3CS-1 and Ralphie / 3CS-2 ~6000 kg Cape Canaveral, SLC-37B Partial failure[a]
2 11 November 2007 DSP-23 Defense Support Program 5250 kg Cape Canaveral, SLC-37B Success
3 18 January 2009 Orion 6 / Mentor 4 (USA-202 / NROL-26) Classified Cape Canaveral, SLC-37B Success
4 21 November 2010 Orion 7 / Mentor 5 (USA-223 / NROL-32) Classified Cape Canaveral, SLC-37B Success
5 20 January 2011 KH-11 Kennen 15 (USA-224 / NROL-49) <17000 kg Vandenberg, SLC-6 Success
6 29 June 2012 Orion 8 / Mentor 6 (USA-237 / NROL-15) Classified Cape Canaveral, SLC-37B Success
7 28 August 2013 KH-11 Kennen 16 (USA-245 / NROL-65) <17000 kg Vandenberg, SLC-6 Success
8 5 December 2014 Orion capsule Exploration Flight Test-1 (EFT-1) 21,000 kg (46,000 lb)[16][b] Cape Canaveral, SLC-37B Success
9 11 June 2016 Orion 9 / Mentor 7 (USA-268 / NROL-37) Classified Cape Canaveral, SLC-37B Success
10 12 August 2018 Parker Solar Probe[c] 685 kg Cape Canaveral, SLC-37B Success
11 19 January 2019 NROL-71 Classified Vandenberg, SLC-6 Success
  1. ^ CBCs underperformed, lower orbit than planned
  2. ^ 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.
  3. ^ Star 48BV upper stage

Upcoming launches[edit]

The following missions have been announced by the National Reconnaissance Office.[17][18] As of August 2020, these are the final five missions.[19]

For these missions including modifications, ULA has been awarded US$2.2 billion, or US$440 million per launch.[20]

Date (UTC) Payload Client Launch site
October 2020
02:00 UTC (12th mission) [21]
NROL-44 NRO Cape Canaveral, SLC-37B
December 2020 (13th mission) NROL-82 NRO Vandenberg, SLC-6
2022 (14th mission) NROL-91 NRO Vandenberg, SLC-6
2022 (15th mission) NROL-68 NRO Cape Canaveral, SLC-37B
2023 (16th mission) NROL-70 NRO Cape Canaveral, SLC-37B

Comparable vehicles[edit]



Retired or cancelled:

See also[edit]


  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 26 July 2014.
  3. ^ a b "Delta IV Payload Planner's Guide, June 2013" (PDF). United Launch Alliance. Archived from the original (PDF) on 10 July 2014. Retrieved 26 July 2014.
  4. ^ "Mission Status Center". SpaceflightNow. Retrieved 26 July 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". New York Times. Retrieved 6 February 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 19 April 2012 at the Wayback Machine, Boeing, 2004, accessed 22 March 2012.
  7. ^ "Delta 4-Heavy likely heading for geosynchronous orbit with top secret payload". Spaceflight Now. 26 August 2020. Retrieved 27 August 2020.
  8. ^ a b c "Delta IV Heavy: Powerful Launch Vehicle". Retrieved 21 July 2018.
  9. ^ "Delta 4-Heavy investigation identifies rocket's problem". Spaceflight Now. Retrieved 26 July 2014.
  10. ^ "Second Stage Ignites as First Stage Falls Away".
  11. ^ a b c "Delta IV Launch Services User's Guide" (PDF). United Launch Alliance. 14 October 2013. pp. 2–10, 5–3. Archived from the original (PDF) on 14 October 2013.
  12. ^ "Delta IV Data Sheet". Space Launch Report. Retrieved 26 July 2014.
  13. ^ Ray, Justin (7 December 2004). "The Heavy: Triple-sized Delta 4 rocket to debut". Spaceflight Now. Archived from the original on 11 December 2004. Retrieved 13 May 2014.
  14. ^ "Live coverage: Launch of Delta 4-Heavy rocket set for early Saturday". Spaceflight Now. 29 August 2020. Retrieved 29 August 2020.
  15. ^ a b Krebs, Gunter. "Delta-4". Gunter's Space Page. Retrieved 15 March 2018.
  16. ^ "NASA Orion Exploration Flight Test-1 PRESS KIT" (PDF). NASA. December 2014. p. 12. This article incorporates text from this source, which is in the public domain.
  17. ^ Ray, Justin (7 June 2016). "Surveillance satellite launching Thursday atop Delta IV Heavy rocket". Spaceflight Now.
  18. ^
  19. ^ Erwin, Sandra (24 August 2020). "ULA to launch Delta IV Heavy for its 12th mission, four more to go before rocket is retired". Retrieved 29 August 2020.
  20. ^ "Air Force awards ULA $1.18 billion contract to complete five Delta IV Heavy NRO missions". 30 September 2019. Retrieved 3 June 2020.
  21. ^ "Launch Schedule". Spaceflight Now. 17 October 2020. Retrieved 17 October 2020.

External links[edit]