USAF.com: Delta II Medium-Launch Vehicle

Delta II Medium Launch Vehicle Delta II rockets can be configured into two-or three-stage vehicles to accommodate a variety of mission requirements. Mission The Delta II is an expendable launch, medium-lift vehicle used to launch Navstar Global Positioning System (GPS) satellites into orbit, providing navigational data to military users. Additionally, the Delta II launches civil and commercial payloads into low-earth, polar, geo-transfer and geosynchronous orbits.

• Features
  
  The Delta II stands a total height of 125.9 feet (37.8 meters). The payload fairing -- the shroud covering the third stage and the satellite -- is 9.5 ft wide to accommodate the GPS satellite. A 10-foot (3.3 meters) wide fairing also is available for larger payloads. Six of the nine solid-rocket motors that ring the first stage separate after one minute of flight, and the remaining three ignite, then separate, after burn-out one minute later.
  
• Background
  
• The Delta launch vehicle family began in 1959 when NASA's Goddard Space Flight Center awarded a contract to Douglas Aircraft Company (now Boeing) to produce and integrate 12 space-launch vehicles. The Delta used components from the U.S. Air Force's Thor intermediate-range ballistic missile as its first stage and the U.S. Navy's Vanguard launch-vehicle program as its second. The first Delta was launched from Cape Canaveral Air Force Station on May 13, 1960 and had the ability to deliver a 100-pound spacecraft into geostationary transfer orbit.
  
• In January 1987 the Air Force awarded a contract to McDonnell Douglas, now Boeing, for construction of 18 Delta IIs to launch Navstar GPS satellites, originally programmed for launch on the space shuttle. Since then, the order expanded to accommodate 28 GPS satellite-dedicated launch vehicles.
  
• The first Delta II was successfully launched on Feb. 14, 1989, at Cape Canaveral. There are two primary versions of the Delta II (6925 and 7925). The Delta 6925, the first version, carried the initial nine GPS satellites into orbit.

1. The Delta program has more than 245 successful domestic and foreign military and commercial launches. The Delta accomplished many firsts over the years. These include the first international satellite, Telstar I, in 1962; the first geosynchronous-orbit satellite, Syncorn II, in 1963; and the first commercial communications satellite, COMSAT I, in 1965.

• The Delta II is launched primarily from Cape Canaveral AFS, Fla., but is also launched from Vandenberg Air Force Base, Calif. Members of Air Force Space Command's 45th Space Wing, with headquarters at Patrick AFB, Fla., and 30th Space Wing at Vandenberg are responsible for the Delta II's military launch missions.

General Characteristics

Primary Function: Space lift vehicle

Builder: Boeing Company, Expendable Launch Systems

Power Plant, first stage: one Rocketdyne RS-27 and two LR-101-NA-11 vernier engines; both use refined kerosene and liquid oxygen as its propellants; thrust (sea level), 200,000 pounds.

Power Plant, second stage: restartable Aerojet AJ10-110K motor; uses nitrogen tetroxide and Aerozine 50 propellants; thrust, 9,750 pounds.

Payload assist module: If used, Star-48B Solid-fuel Rocket, 14,920 pounds. Nine Alliant Techsystems strap-on graphite-epoxy motors surround the first stage for augmented lift-off; thrust 100,270 pounds.

Thrust (at liftoff): 699,250 pounds

Launch Sites: Space Launch Complex 17, Cape Canaveral AFS, Fla.; Space Launch Complex 2, Vandenberg AFB, Calif.

Height: 125 feet, 9 inches (38.32 meters)

Diameter: Fairing -- 9.5 feet (2.87 meters), core -- 8 feet (2.4 meters)

Weight: 511,190 pounds (231,870 kilograms)

Lift Capability: The Delta II can carry payloads into near-earth orbits (approximately 100 nautical miles 160 kilometers in space). It can lift up to 11,100 pounds (4,995 kilograms) into a 28-degree circular near-earth orbit and up to 8,420 pounds (3,789 kilograms) into a 90-degree polar near-earth orbit. The Delta II also can carry up to 4,010 pounds (1,804.5 kilograms) into geo-transfer orbit (approximately 12,000 miles 19,200 kilometers) and up to 2,000 pounds (909 kilograms) into geosynchronous orbit (approximately 22,000 miles 35,200 kilometers).

Payloads: The three-stage Delta 7925 has carried 29 GPS Block II satellites into orbit, with another 19 slated to launch as needed. The National Reconnaissance Office's GeoLITE payload will also use a Delta 7925. A two-stage Delta 7920 launched the Advanced Research and Global Observation Satellite, an Air Force Space Test Program mission.

Guidance System: Delta Redundant Inertial Flight Control Assembly manufactured by Allied Signal Aerospace

Date Deployed: November 26, 1990 (7920/7925 series)

Unit cost: Not available

Inventory: Active force, 2 (with more on order)

Point of Contact

Air Force Space Command
Public Affairs Office
150 Vandenberg St.
Suite 1105
Peterson AFB, CO 80914-4500
DSN 692-3731, or (719) 554-3731

Above Information Courtesy of United States Air Force

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