Delta IV

Delta IV

Delta IV Medium launch carrying DSCS III-B6.
Function	Orbital launch vehicle
Manufacturer	United Launch Alliance
Country of origin	United States
Cost per launch	US$164+ million[1]
Size
Height	63.0–70.7 m (206.7–232.0 ft)
Diameter	5.1 m (17 ft)
Mass	249,500–733,400 kg (550,100–1,616,900 lb)
Stages	2
Capacity
Payload to LEO
Mass	11,470–28,790 kg (25,290–63,470 lb)[2]
Payload to GTO
Mass	4,440–14,220 kg (9,790–31,350 lb)
Associated rockets
Family	Delta (rocket family)
Comparable	Atlas V Falcon 9 H-IIA Long March 5 Proton-M
Launch history
Status	Retired
Launch sites	Cape Canaveral, SLC-37 Vandenberg, SLC-6
Total launches	45[3][4]     Medium: 3     M+ (4,2): 15     M+ (5,2): 3     M+ (5,4): 8     Heavy: 16
Success(es)	44     Medium: 3     M+ (4,2): 15     M+ (5,2): 3     M+ (5,4): 8     Heavy: 15
Partial failure(s)	1 (Heavy Demo)
First flight	Medium/M+: 20 November 2002 (Eutelsat W5) Heavy: 21 December 2004 (USA-181)
Last flight	Medium/M+: 22 August 2019 (USA-293/GPS III-2) Heavy: 9 April 2024 (NROL-70)
Type of passengers/cargo	GOES GPS Block IIF NRO classified payloads WGS Exploration Flight Test 1 Parker Solar Probe
Boosters (Medium+) – GEM 60
No. boosters	2[a] or 4[b]
Gross mass	33,638 kg (74,158 lb)
Maximum thrust	826.6 kN (185,800 lbf)
Specific impulse	SL: 245 s (2.40 km/s)
Burn time	91 seconds
Propellant	AP / HTPB / Al
Boosters (Heavy) – CBC
No. boosters	2
Gross mass	226,400 kg (499,100 lb)
Powered by	1 × RS-68A
Maximum thrust	3,140 kN (705,000 lbf) (sea level)
Specific impulse	SL: 360 s (3.5 km/s) vac: 412 s (4.04 km/s)
Burn time	242 seconds[2]
Propellant	LH2 / LOX
First stage – CBC
Gross mass	226,400 kg (499,100 lb)
Powered by	1 × RS-68A
Maximum thrust	3,140 kN (705,000 lbf) (sea level)
Specific impulse	SL: 360 s (3.5 km/s) vac: 412 s (4.04 km/s)
Burn time	245 seconds (328 seconds in Heavy configuration)[2]
Propellant	LH2 / LOX
Second stage – DCSS
Gross mass	4-m: 24,170 kg (53,290 lb) 5-m: 30,700 kg (67,700 lb)
Powered by	1 × RL10-B-2
Maximum thrust	110 kN (25,000 lbf)
Specific impulse	462 s (4.53 km/s)
Burn time	850–1,125 seconds
Propellant	LH2 / LOX
[edit on Wikidata]

Delta IV was a group of five expendable launch systems in the Delta rocket family. It flew 45 missions from 2002 to 2024. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV was primarily a launch vehicle for United States Air Force (USAF) military payloads, but was also used to launch a number of United States government non-military payloads and a single commercial satellite.

The Delta IV had two main versions which allowed the family to cover a range of payload sizes and masses: the Medium (which had four configurations) and Heavy. The final flight of Medium occurred in 2019. The final flight of Heavy was in April 2024.

Delta IV vehicles were built in the ULA facility in Decatur, Alabama.^[5] Final assembly was completed at the launch site by ULA: at the horizontal integration facility for launches from SLC-37B pad at Cape Canaveral and in a similar facility for launches from SLC-6 pad at Vandenberg Space Force Base.

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