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Delta IV Heavy

Delta IV Heavy launches from Vandenberg AFB
Function	Orbital heavy-lift launch vehicle
Manufacturer	United Launch Alliance
Country of origin	United States
Cost per launch	$350 million[1] (2018)
Size
Height	72 m (236 ft)
Diameter	5 m (16 ft)
Width	15 m (49 ft)
Mass	733,000 kg (1,616,000 lb)
Stages	2+
Capacity
Payload to LEO	28,790 kg (63,470 lb)
Payload to GTO	14,220 kg (31,350 lb)
Associated rockets
Family	Delta IV
Comparable	Ariane 5 Falcon Heavy Long March 5 New Glenn Proton-M Vulcan
Launch history
Status	Active
Launch sites	SLC-37B, Cape Canaveral SLC-6, Vandenberg AFB
Total launches	10
Successes	9
Partial failures	1
First flight	21 December 2004 (USA-181)
Last flight	12 August 2018 (Parker Solar Probe)
Notable payloads	EFT-1 NRO classified payloads Kennen Orion Parker Solar Probe
Boosters (CBC)
No. boosters	2
Length	40.8 m (134 ft)
Diameter	5.1 m (17 ft)
Empty mass	26,000 kg (57,000 lb)
Gross mass	226,400 kg (499,100 lb)
Propellant mass	200,400 kg (441,800 lb)[2]
Engines	1 RS-68A
Thrust	3,140 kN (710,000 lbf)
Total thrust	6,280 kN (1,410,000 lbf)
Specific impulse	Sea level: 360 s (3.5 km/s) Vacuum: 412 s (4.04 km/s)
Burn time	242 seconds[3]
Fuel	LH2 / LOX
First stage (CBC)
Length	40.8 m (134 ft)
Diameter	5.1 m (17 ft)
Gross mass	226,400 kg (499,100 lb)
Propellant mass	200,400 kg (441,800 lb)
Engines	1 RS-68A
Thrust	3,140 kN (710,000 lbf)
Specific impulse	Sea level: 360 s (3.5 km/s) Vacuum: 412 s (4.04 km/s)
Burn time	328 seconds
Fuel	LH2 / LOX
Second stage (DCSS)
Length	13.7 m (45 ft)
Diameter	5.1 m (17 ft)
Gross mass	30,700 kg (67,700 lb)
Propellant mass	27,220 kg (60,010 lb)
Engines	1 RL10-B-2
Thrust	110 kN (25,000 lbf)
Specific impulse	462 s (4.53 km/s)
Burn time	1,125 seconds
Fuel	LH2 / 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.^[4][5] It is manufactured by United Launch Alliance and was first launched in 2004.^[6]

The Delta IV Heavy uses two additional Common Booster Cores (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]

History

Delta IV Heavy for EFT-1, 2014

The Delta family of rockets was developed by McDonnell Douglas, later United Launch Alliance, and the Delta IV Heavy is heavier lifting version of family compared to smaller rockets like the 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 a overall 2 stage rocket, with two strap-on boosters, all liquid-fuel rockets.^[7]

The first launch of the Delta IV Heavy in 2004 carried a boilerplate payload (dummy 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.^{[citation needed]}

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]

When introduced, the Delta IV Heavy had the largest payload capability of all operational rockets. It was overtaken in February 2018 with the maiden launch of the SpaceX Falcon Heavy.^[11]

Capability

Capacity of the Delta IV Heavy:

• 
  Low Earth orbit (LEO), 200 km × 28.7°: 28,790 kg (63,470 lb)^[12]
  


• Low Earth orbit (ISS), 407 km × 51.6°: 25,980 kg (57,280 lb)^[13]
  


• 
  Geosynchronous transfer orbit (GTO): 14,220 kg (31,350 lb)^[12]
  


• 
  Geosynchronous orbit (GEO): 6,750 kg (14,880 lb)^[12]
  


• 
  Lunar transfer orbit (LTO): 10,000 kg (22,000 lb)


• 
  Mars transfer orbit: 8,000 kg (17,600 lb)^[14]
  

The Delta IV Heavy's total mass at launch is approximately 733,000 kg (1,616,000 lb). For comparison, the total mass at launch of the Saturn V used in the Apollo program was 2,970,000 kg (6,550,000 lb).

Launch history

^A Launched from Cape Canaveral, SLC-37B
^B Launched from Vandenberg, SLC-6
^C CBCs underperformed, lower orbit than planned
^D Star 48BV upper stage

Upcoming launches

The following missions have been announced by NASA and the National Reconnaissance Office.^[16]

Comparable vehicles

See also

• Heavy-lift launch vehicle


• Comparison of orbital launch systems


• Comparison of orbital rocket engines


• Comparison of space station cargo vehicles


• 
  National Launch System, (1991–1993) study

References

External links

• Delta IV Booster Integration Another Step Toward First Orion Flight