Delta IV Heavy
Delta IV Heavy launches from Vandenberg AFB
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| Function | Orbital heavy lift launch vehicle |
|---|---|
| Manufacturer | United Launch Alliance |
| Country of origin | United States |
| Cost per launch | $375 million (2016) |
| 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 |
| Launch history | |
| Status | Active |
| Launch sites | |
| Total launches | 9 |
| Successes | 8 |
| Partial failures | 1 |
| First flight | December 21, 2004 |
| Boosters (CBC) | |
| No. boosters | 2 |
| 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) |
| Total thrust | 6,280 kN (1,410,000 lbf) |
| Specific impulse |
Sea level: 360 sec Vacuum: 412 sec |
| Burn time | 242 seconds |
| 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 sec Vacuum: 412 sec |
| 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 highest capacity rocket currently in operation. It is manufactured by United Launch Alliance and it was first launched in 2004.
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.
The first launch of the Delta IV Heavy in 2004 carried a boilerplate payload, and was a partial failure. Cavitation in the liquid oxygen propellant lines caused shutdown of both boosters 8 seconds early, and the core engine 9 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. 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, the mission was successfully launched at 12:05 UTC on December 5.
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