Delta IV EELV - McDonnell-Douglas

Delta IV EELV - Boeing

The Evolved Expendable Launch Vehicle Program (EELV) was a multi-year U.S. Air Force program aimed at reducing space launch costs up to 50 percent from an existing rate of approximately $12,000 per pound of payload to orbit. The program included three classes of launch vehicles: Small (4,800 pounds to geosynchronous transfer orbit (GTO)), Medium (10,000 pounds to GTO) and Heavy (33,000 pounds to GTO). To meet these requirements McDonnell Douglas designed the Delta IV family of launch vehicles.

The Air Force selection of two contractors in December 1996 moved McDonnell Douglas and Lockheed Martin forward to Module II of the EELV program, Pre-Engineering, Manufacturing and Development (Pre-EMD). Pre-EMD was a firm fixed-priced 17-month contract worth $60 million for each company. The final module, EMD, was expected to be a winner-take-all to develop the EELV family with the first test flight in 2001. The EMD contract value was $1.4 billion.

All Delta IV configurations share a common booster core (CBC), a low-cost design that was optimized for high-performance, environmentally compatible liquid oxygen/liquid hydrogen fuel. In the Delta tradition of high reliability, the CBC featured a single booster engine. The initial three configuration were:

• Delta IV-Small CBC, proven Delta II hyperbolic upper stage, optional Delta II third stage, and Delta II 10-ft diameter composite fairing
• Delta IV-Medium CBC, Delta III upper stage, and Delta III 4-m fairing
• Delta IV-Heavy CBC, 2 strap-on CBCs, Delta III upper stage with extended tanks, Titan IV 200-in. fairing

Common across all is the Delta family suite of fault-tolerant avionics, flight-proven core software, and standardized launch pads, facilities, equipment, and processes.

The three configurations were designed to meet the National Mission Model payload and performance requirements. These vehicles spanned the mass-to-orbit requirements for government and commercial spacelift, at the time and expected to be in the future. In addition, consistent Delta reliability and launch responsiveness would ensure a continuous and growing commercial market for Delta IV for sustainable cost savings to the government. Delta IV was sized to accommodate geosynchronous transfer orbit (GTO) loads greater than any existing launch system, at substantially lower cost. McDonnell Douglas matched payload weights to each configuration with appropriate margin for growth with the intent of a resulting design that balanced performance with cost.

Key to the McDonnell Douglas entry was development of a revolutionary low-cost engine design by the Rocketdyne Division of Boeing North American, Inc. The RS-68 burns liquid oxygen and liquid hydrogen that produced a dramatic 30 percent gain in performance over existing conventional liquid oxygen and kerosene-fueled engines. The design for all three Delta IV variants would use this 650,000-pound-thrust common booster core engine. Designed to the low end of LO 2 /LH 2 performance, the RS-68 engine did not rely on new technology, exotic materials, or tight-tolerance manufacturing processes. The RS-68 used fewer parts (7% of the Space Shuttle Main Engine), a conventionally fabricated coaxial injector, low-speed single-stage centrifugal turbopumps, a low-pressure chamber design evolved from the J-2, and an available bolt-on nozzle. A major main engine component was successfully tested 31 October 1996 at NASA's Marshall Space Flight Center in Huntsville, AL, when liquid oxygen and hydrogen were ignited in the thrust chamber of the RS-68 main booster engine.

Delta II or III upper stages, evolved over decades of reliable Delta service, were added to the common booster core to complete each vehicle. For example, the Delta IV Small rocket added the Delta II second stage, optional third stage and 10-foot-diameter composite fairing. The Delta IV Medium would add the cryogenic second stage engine of the Delta III, and the Delta III composite, 13.1-foot-diameter fairing for payload protection. The proven McDonnell-Douglas-built Titan IV fairing and a modified Delta III second stage would be incorporated on the Delta IV heavy.

Launch preparations and testing were planned to take place at Cape Canaveral Air Station, Florida, and at Vandenberg Air Force Base, California. A new launch pad, mobile service tower and horizontal integration facility were to be built at Space Launch Complex 37 at Cape Canaveral to handle launches. Space Launch Complex 6 at Vandenberg would be modified for Delta IV launches. Both sites would process rockets horizontally, away from the launch pad, to reduce pre-launch on-pad time from 24 days to only six-to-eight days.

To lower cost and increase flexibility, Delta IV was integrated horizontally in a dedicated facility at each launch site. This facility was intended to support the integration of several Delta IVs simultaneously. Mobile elevated platform transporters were to move vehicle stages around the launch site, and in the integration facility to mate CBCs and upper stages. The transporters would save time and personnel costs, and eliminate hazardous crane operations for core vehicle buildup. Horizontal processing of launch vehicles was expected to take less than one-half the time of vertical processing.

Major subcontractors for the Delta IV include:

• Rocketdyne Division of Boeing North American, Inc., Canoga Park, Calif., RS-68 first-stage main engine.
• Aerojet, Sacramento, Calif., second-stage engine for the Delta IV Small
• Pratt & Whitney, West Palm Beach, Fla., second-stage engines for the Delta IV Medium and Heavy.
• AlliedSignal Aerospace, Teterboro, N.J., Redundant Inertial Flight Control Assembly (RIFCA) for guidance control of all Delta IVs.

Others include Thiokol Defense and Launch Vehicles, Cincinnati Electronics, Corp., Gulton Data Systems, Raytheon Engineers and Constructors, Spincraft Division of Standex Precision Engineering and United Technologies.

In 1997 McDonnell-Douglas merged with Boeing, with Boeing's Launch Services becoming the primary contractor for the Delta rocket family.