 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 | 63–72 m (207–236 ft) |
| Diameter | 5 m (16 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) |
| Payload to GTO | |
| Mass | 4,440–14,220 kg (9,790–31,350 lb) |
| Associated rockets | |
| Family | Delta (rocket family) |
| Comparable | |
| Launch history | |
| Status | Delta IV Heavy is active; Delta IV Medium, M+(4,2), M+(5,2), and M+(5,4) retired. |
| Launch sites | SLC-37B, Cape Canaveral SLC-6, Vandenberg AFB |
| Total launches | 44
|
| Success(es) | 43
|
| Partial failure(s) | 1 (Heavy) |
| First flight |
|
| Last flight | |
| Type of passengers/cargo | |
| Boosters (Medium+) – GEM 60 | |
| No. boosters | Medium+ (4,2), Medium+ (5,2): 2 Medium+ (5,4): 4 |
| Gross mass | 33,638 kg (74,158 lb) |
| Powered by | off |
| Maximum thrust | 826.6 kN (185,800 lbf) |
| Specific impulse | 245 s (2.40 km/s) (sea level) |
| Burn time | 91 seconds |
| Propellant | HTPB / Aluminum |
| Boosters (Heavy) – Common Booster Core (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 | Sea level: 360 s (3.5 km/s) Vacuum: 412 s (4.04 km/s) |
| Burn time | 242 seconds |
| Propellant | LH2 / LOX |
| First stage – Common Booster Core (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 | Sea level: 360 s (3.5 km/s) Vacuum: 412 s (4.04 km/s) |
| Burn time | 245 seconds (328 seconds in Heavy configuration) |
| Propellant | LH2 / LOX |
| Second stage – Delta Cryogenic 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 |
Delta IV is a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. 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 is primarily a launch vehicle for United States Air Force (USAF) military payloads, but has also been used to launch a number of United States government non-military payloads and a single commercial satellite.[2]
The Delta IV originally had two main versions which allowed the family to cover a range of payload sizes and masses: the retired Medium (which had four configurations) and Heavy.[3] As of 2019, only the Heavy remains active, with payloads that would previously fly on Medium moving to either the existing Atlas V or the forthcoming Vulcan. Retirement of the Delta IV is anticipated in 2024.[4]
Delta IV vehicles are built in the ULA facility in Decatur, Alabama. Final assembly is 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 Air Force Base.[2]
The following missions have been announced by the National Reconnaissance Office.[36] For the final five missions (12-16) including contract modifications, ULA has been awarded $2.2 billion, or $440 million per launch.[37] This can be compared with the Falcon Heavy launch price of $90 million to $150 million. As of July 2021, these are the final missions:[38]
| Date (UTC) | Payload | Client | Launch site |
|---|---|---|---|
| March 2024 (16th mission) | NROL-70 | NRO | Cape Canaveral, SLC-37B |
