Tim Furniss/LONDON
GenCorp Aerojet has won a $500 million contract to build solid rocket motors (SRMs) for the Lockheed Martin Evolved Expendable Launch Vehicle (EELV). The US launcher builder has also changed the name of the EELV to the Atlas V.
The addition of the SRMs has been made to enable the Atlas V to compete more effectively in the commercial market, particularly against the Boeing Delta IV EELV.
The SRMs will be based on Minuteman and Peacekeeper missiles. Up to five will be fitted to the Heavy and Medium versions of the Atlas V, depending on the mission requirement, adding versa0tility to the US Air Force and commercial market variants.
The most powerful Atlas, the Atlas V Heavy, with three liquid-propellant Common Core Boosters (CCBs) strapped together and a new Centaur upper stage with two RL-10 engines, will be able to place 6,500kg directly into geostationary orbit and 13,000kg into geostationary transfer orbit (GTO). Added SRMs will be able to increase this capability as required, with a GTO goal of about 14,500kg.
The Atlas V Medium will consist of a single CCB and a Centaur stage, with one or two RL-10s, and, bolstered by five SRMs, could place 5,000kg to GTO. The first Medium booster was baselined for a 3,900kg-to-GTO capability.
The CCB is based on the new Atlas III booster which will be equipped with a single Russian NPO Energomash/Pratt & Whitney RD-180 liquid-oxygen/kerosene engine. The Atlas IIIA has its debut this year.
Boeing has also added SRMs, to be supplied by Alliant TechSystems, to its original EELV concept. Two or four SRMs added to the Delta IV Medium will enable the most powerful model to place 6,670kg to GTO.
The Delta IV and Atlas V fleets - which are built under $3 billion USAF contracts - will also serve the commercial market, posing the biggest threat yet to confront Arianespace's Ariane 5.
Source: Flight International
