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Delta II Medium Launch Vehicle

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.

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History

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.

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.

Description

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.

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