Expendable Launch Vehicle, known as EELV, is designed to improve our nation¡¦s access to space by making space launch vehicles more affordable and reliable. The program is replacing the existing fleet of launch systems with two families of launch vehicles, each using common components and common infrastructure. The vehicles are the Boeing Delta IV and Lockheed Martin Atlas V. EELV¡¦s operability improvements over current systems include a standard payload interface, standardized launch pads and increased off-pad processing.
CAPE CANAVERAL AIR FORCE STATION, Fla. -- A Boeing Delta IV heavy launch vehicle lifted off from here on a demonstration mission for the Air Force's evolved expendable launch vehicle program. The mission is to send the satellite into a geosynchronous Earth orbit. (U.S. Air Force photo by Carleton Bailie)
The Evolved Expendable Launch Vehicle (EELV) program provides the United States affordable, reliable, and assured access to space with two families of launch vehicles: Atlas V and Delta IV. These launch vehicles provide critical spacelift capability to support Department of Defense and other National Security missions (together known as National Security Space (NSS) missions). With multiple launch vehicle configurations and launch sites on both coasts of the U.S., EELV has a proven track record of success, demonstrating unprecedented reliability with 54 successful launches since 2002. Of those 54 launches, 30 have been EELV National Security Space launches in support of the Navy, National Reconnaissance Office and the Air Force.
The EELV program's Delta IV and Atlas V launch vehicles are produced by United Launch Alliance (a joint venture of Boeing and Lockheed Martin formed in 2006). In addition to manufacturing the launch vehicles, ULA also maintains space launch complexes at Cape Canaveral Air Force Station, Fla, and Vandenberg Air Force Base, Calif. Program cost savings are achieved through operability improvements such as the use of common components and infrastructure, a standard payload interface, standardized launch pads and reduced on-pad processing; and acquisition improvements such as launch vehicle block buys.
As the Air Force's spacelift modernization program, EELV was designed to increase reliability and reduce launch costs by at least 25 percent over heritage Atlas, Delta and Titan space launch systems. The EELV program was initiated in 1994 and planned to be a "rolling-downselect" of launch vehicle providers from four to one. In 1998, when it appeared the growth in the commercial satellite industry would be able to sustain two providers of launch services. the Air Force decided to award contracts to both Boeing and Lockheed Martin for their respective launch capabilities. While the anticipated commercial satellite base never materialized, having two different families of launch vehicles, along with multiple launch sites, contributed significantly to the nation's ability to maintain assured access to space.
A new EELV Acquisition Strategy was approved in November 2011 which recognizes only the Atlas V and Delta IV can currently provide reliable launch services to meet NSS requirements but also seeks to take advantage of the growing potential of additional commercial space launch providers. The approach continues procurement of launch services and launch capability from ULA for the next several years but provides for a full and open competitive environment for any alternative sources as soon as they are certified. The primary goal remains 100% mission success while incentivizing cost reductions. Steady production rates, long-term commitments and opportunities for competition are among the means to achieve this goal.
The Evolved Expendable Launch Vehicle (EELV) program is managed by the Launch and Range Systems Directorate of the Space and Missile Systems Center (Air Force Space Command), Los Angeles Air Force Base, Calif.
EELV Launch Vehicles
The Delta IV family is capable of carrying over 12,247 kg (27,000 lbm) to geosynchronous transfer orbit, and can lift over 9,979 kg (22,000 lbm) to low-Earth orbit. The Delta IV Medium, Medium-Plus and Heavy configurations are evolved from flight proven Delta II and Delta III systems while incorporating the latest technology into a family of vehicles maximizing the use of common hardware.
The Medium & Medium-Plus vehicles use a single Common Booster Core (CBC), while the Heavy variant uses three CBCs. The Pratt & Whitney Rocketdyne -built RS-68, a liquid hydrogen/liquid oxygen engine that produces 663,000 lbs of liftoff thrust, powers the first stage. Launch performance can be augmented by adding either two or four solid rocket motors. The second stage is powered by the RL10B engine. Either a 4m or 5m fairing encapsulates the payload. Vehicles are defined by the number of solids and the width of the payload fairing.
Delta IV's inaugural flight was marked by the successful launch of a commercial satellite on a Medium-Plus (4,2) in November 2002. The first Heavy vehicle (demo) was launched in December 2004.
The Atlas V family is capable of carrying payloads over 8,618 kg (19,000 lbm) to geosynchronous transfer orbit, and can lift over 15,442 kg (34,000 lbm) to low-Earth orbit. The Atlas V provides medium and intermediate lift capability and is evolved from flight-proven Atlas and Titan programs, maximizing flexibility and reliability. The Atlas family of launch vehicles has and continues to be a national workhorse, logging nearly 600 total launches (NSS, civil, and commercial) to date.
The Atlas V family uses a Russian RD-180 to power the first stage Common Core Booster. It uses 627,105 lbs. (284,453 kg) of liquid oxygen and RP-1 rocket fuel propellants. Up to five solid rocket boosters can be added to augment performance. The second stage (known as Centaur) is powered by the RL10A engine. As with the Delta IV, either a 4m or 5m fairing is used to shroud the payload, and vehicles are defined by the number of solids and the size of the payload fairing. Currently there are no requirements for an Atlas V Heavy.
The Atlas V's inaugural flight was marked by the successful launch of a Hotbird-6 commercial satellite in August 2002.