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Delta II 7925

Delta II
Delta II Dawn liftoff 1.jpg
A Delta II rocket launches from Cape Canaveral carrying the Dawn spacecraft.
Function Launch vehicle
Manufacturer United Launch Alliance (Boeing IDS)
Country of origin United States
Cost per launch US$51 million in 1987 (7920-10 mod.)
Size
Height 38.2–39 m (125–128 ft)
Diameter 2.44 m (8 ft 0 in)
Mass 151,700–231,870 kg (334,440–511,190 lb)
Stages 2 or 3
Capacity
Payload to LEO 2,700–6,100 kg (6,000–13,400 lb)
Payload to GTO 900–2,170 kg (1,980–4,780 lb)
Payload to HCO 1,000 kg (2,200 lb)
Launch history
Status
  • Delta 6000: Retired
  • Delta 7000: Active
  • Delta 7000H: Retired
Launch sites Cape Canaveral SLC-17
Vandenberg AFB SLC-2W
Total launches 155
Delta 6000: 17
Delta 7000: 131
Delta 7000H: 6
Successes 153
Delta 6000: 17
Delta 7000: 129
Delta 7000H: 6
Failures 1 (Delta 7000)
Partial failures 1 (Delta 7000)
First flight
Last flight
  • Delta 6000: 24 July 1992 (Geotail)
  • Delta 7000: 18 November 2017 (JPSS-1)
  • Delta 7000H: 10 September 2011 (GRAIL)
Boosters (6000 Series) – Castor 4A
No. boosters 9
Motor Solid
Thrust 478 kN (107,000 lbf)
Specific impulse 266 s
Burn time 56 s
Fuel HTPB
Boosters (7000 Series) – GEM 40
No. boosters 3, 4, or 9
Motor Solid
Thrust 492.9 kN (110,800 lbf)
Specific impulse 274 s
Burn time 64 s
Fuel HTPB
Boosters (7000 Heavy) – GEM 46
No. boosters 9
Motor Solid
Thrust 628.3 kN (141,200 lbf)
Specific impulse 278 s
Burn time 75 s
Fuel HTPB
First stage – Thor/Delta XLT(-C)
Engines 1 RS-27 (6000 series) or RS-27A (7000 series)
Thrust 1,054 kN (237,000 lbf)
Specific impulse 302 s
Burn time 265 s
Fuel LOX/RP-1
Second stage – Delta K
Engines 1 AJ10-118K
Thrust 43.6 kN (9,800 lbf)
Specific impulse 319 s
Burn time 431 s
Fuel N2O4/Aerozine 50
Third stage – PAM-D (optional)
Motor Star 48B
Thrust 66 kN (15,000 lbf)
Specific impulse 286 s
Burn time 87 s
Fuel HTPB

Delta II is an American expendable launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and entered service in 1989. Delta II vehicles included the retired Delta 6000, and the two currently-used Delta 7000 variants ("Light" and "Heavy"). In 2018, the rocket is scheduled to fly its final mission, ICESat-2, which will earn the launch vehicle a streak of 100 successful missions in a row if successful.

In the early 1980s, all United States expendable launch vehicles were planned to be phased out in favor of the Space Shuttle, which would be responsible for all government and commercial launches. Production of Delta, Atlas-Centaur, and Titan 34D had ended. The Challenger disaster of 1986 and the subsequent halt of Shuttle operations changed this policy, and President Ronald Reagan announced in December of that year that the Space Shuttle would no longer launch commercial payloads, and NASA would seek to purchase launches on expendable vehicles for missions that did not require crew or Shuttle support.McDonnell Douglas, at that time the manufacturer of the Delta family, signed a contract with the U.S. Air Force in 1987 to provide seven Delta IIs. These were intended to launch a series of GPS Block II satellites, which had previously been manifested for the Space Shuttle. The Air Force exercised additional contract options in 1988, expanding this order to 20 vehicles, and NASA purchased its first Delta IIs in 1990 for the launch of three Earth-observing satellites. The first Delta II launch occurred in 1989, with a Delta 6925 boosting the first GPS Block II satellite into a 20,000 km high orbit.

The first Delta II 7000-series flew in 1990, replacing the RS-27 engine of the 6000-series with the more powerful RS-27A. Additionally, the steel-cased Castor 4A solid boosters of the 6000 series were replaced with the composite-cased GEM 40. All further Delta II launches except three were of this upgraded configuration, and the 6000-series was retired in 1992.


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