(U) Delta II

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)

Overview: (U)
(U) The active Delta launch vehicle is the Delta II 7925.  The Delta II launch vehicle consists of a liquid-fueled core vehicle with 9 solid strap-on boosters.  The larger strap-on boosters of the Delta II 7925 and different first stage engine allows for greater payload capability.  Delta IIs are launched from SLC17-A/B at Cape Canaveral AFS, FL, and Space Launch Complex - 2 West (SLC-2W) at Vandenberg AFB, CA.  The typical launch processing time for the Delta II is 76 days. 

Description: (U)
(U) The Air Force Delta II 7925 spacelift system supports DoD medium class missions.  The Delta II, built by Boeing, stands 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 is also available for larger payloads.  The booster has the capability to place payloads into semi-synchronous (3,670 lbs), low earth (11,100 lbs), or Geosynchronous Transfer Orbit (GTO) (3,690 lbs). The Delta II launch vehicle consists of a liquid-fueled core with 9 solid strap-on boosters. The vehicle includes new solid-rocket motors with cases made of graphite-epoxy. Built by Alliant Techsystems, the motor cases are lighter but as strong as the steel cases they replaced. The new motors are six feet longer and provide greater thrust.  The main-engine nozzle on the first stage has also been enlarged, giving a greater expansion ratio for improved performance.  At launch, the main-engine nozzle and six of the solid-rocket motors fire.  The six solid-rocket motors separate after one minute of flight, and the remaining three ignite and separate after burn-out one minute later. 

(U) Delta's origins go back to the Thor intermediate-range ballistic missile, which was developed in the mid-1950s for the U.S. Air Force.  The Thor, a single-stage liquid-fueled rocket, later was modified to become the Delta launch vehicle. 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. The first Delta II was successfully launched on Feb. 14, 1989, at Cape Canaveral.  The Delta II 7925 began launching GPS satellites in November 1990. 

(U)  The Delta II was specifically purchased by the Air Force to support the launching of the Global Positioning System (GPS) satellite constellation.  The Medium Launch Vehicle (MLV) Delta II deployed 24 GPS II/IIA satellites to reach the constellation's Full Operational Capability (FOC).  The MLVIII Delta II will replenish the GPS constellation with 4 Launch-To-Sustain (LTS) GPS missions as well as 21 GPS IIR satellites through FY 2002.  One Space Test Program mission will also be launched in FY98.  The Delta II has also been used for launches of the Midcourse Space Experiment (MSX), the Iridium mobile satellite system, Globalstar, and the Canadian RADARSAT.  

(U)  On 5 November 1997, the 28th and final launch of a GPS Block IIA satellite was accomplished.  A Boeing Delta II booster launched the satellite from Cape Canaveral into a 10,993 X 100 nm transfer orbit inclined 35 degrees.  The spacecraft's apogee kick motor later placed the satellite into its 11,000 nm operational orbit.  

(U) Upgrades to the Delta II incorporated by the MLV III program include: 

- (U)  Responsiveness - 40 day launch to-sustain for GPS IIR.

- (U)  Performance upgrade - Baseline 5% system margin above requirement of 4,480 lbs to semi-synchronous transfer orbit. Performance option for Air Force to increase up to 11%.

- (U)  Standard Payload Interface - MLV III and GPS IIR define the standard interface for all MLV III launches of other DoD payloads.

- (U)  Range Safety Compliance - MLV III has no range safety waivers in compliance with AFR 127-1.  Safety Equivalence Reports (SERS) will be considered if they meet the intent of AFR 127-1 and Range Safety regulations.

- (U)  Standard Air Force Logistics implementation - Type I System Training.

- (U)  1SLS Operations Building (1SLS OB) - The 1SLS OB moves the administrative and launch control functions out of the Launch Danger Area. This facility corrects a major safety deficiency in Delta II operations and paves the way for the development of more capable launch systems, like the Delta III.

- (U)  Reliability/Availability - Total system reliability is 95%, vehicle reliability is 98%, and the ground element reliability is 99.9%. System availability is 90%.

User Impact: (U)
(U) Provides medium-lift capability to launch surveillance, communications, global positioning, weather and exploratory satellites which support commercial, DoD and national requirements.

Programmatics: (U)
(U) Operational.
	(U) Termination: 01/2004 (2QFY2004).
		(U)  The termination date for Delta II is the last launch which is expected to occur in FY04.

Related Initiatives: (U)
(U) Eastern Range, GPS Block IIA, GPS Block IIF, GPS Block IIR, Mid-Course Space Experiment, SBIRS-Low, Western Range

Related Requirements: (U)
(U) None.

Related Categories: (U)
(U) Launch, Launch Vehicles, Spacelift

Road Map Placements: (U)
(U) Major DoD Space Programs, National Security Space Road Map, SPACE FORCES SUPPORT.

Lead Office: (U)
(U) Air Force.

Date of Information: (U)
05 November 1997

(The effects of any budget/program decisions made since the information was collected during 1997-98 are NOT reflected in the National Security Space Road Map (NSSRM).)