The Delta II is an expendable launch, medium-lift vehicle used to launch Global Positioning System satellites into orbit, providing navigational data to military users. Additionally, the Delta II launches civil and commercial payloads into low-earth, polar, geosynchronous transfer and stationary orbits.
The Delta II stands a total height of 125.75 feet (38.32 meters). The payload fairing -- the shroud covering the third stage and the satellite -- is 2. 9 meters (9.5 feet) wide to accommodate the GPS satellite. A 3-meter (10 feet) stretched version 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.
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, Fla., 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 GPS satellites, originally programmed for launch on the space shuttle. The Delta II remains the U.S. Air Force's sole launch platform for placing GPS IIR satellites in orbit.
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.
Since May 1960, the Delta program has more than 270 successful military, civil 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 from Cape Canaveral AFS and 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 AFB are responsible for the Delta II's military launch missions.
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. Nine Alliant Techsystems strap-on graphite-epoxy motors surround the first stage for augmented lift-off; thrust, 100,270 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.
Thrust (at liftoff): 699,250 pounds
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 low earth orbit, 28-degree circular near-earth orbit and up to 8,420 pounds (3,789 kilograms) into a 90-degree polar 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: DOD Global Positioning System; civil and commercial satellites
Guidance System: Delta Redundant Inertial Flight Control Assembly manufactured by Allied Signal Aerospace
Date Deployed: Nov. 26, 1990 (7920/7925 series)
Launch Sites: Space Launch Complex 17 Pads A and B, Cape Canaveral AFS, Fla.; Space Launch Complex 2 West, Vandenberg AFB, Calif.
Unit cost: Not available
Inventory: Not available