Slip to late August comes as initial number of Evolved Expendable launch missions are below projections

The first flight of Boeing's Delta IV Evolved Expendable Launch Vehicle (EELV) has been delayed again to give more time to prepare the vehicle.

Although the latest slippage is only a matter of weeks - from mid-July to late August - the Delta IV was originally planned to undertake its first mission in early 2002. The vehicle will carry Eutelsat'sW5 commercial communications satellite on its first commercial launch.

Meanwhile, the number of initial launches planned for the US Air Force EELV programme by Delta IVs and the Lockheed Martin Atlas V are falling short of the predicted numbers.

The Delta IV has 22 EELV contracts, compared with the Atlas V's seven - down from an original nine. Over 40% of the launches originally predicted up to 2007 have been pushed into the 2008-12 period by delays to several programmes, including the deployment of new Block IIF global positioning system satellites.

Five Delta IV models are planned and have already been allocated EELV flights, carrying two weather and two communications satellites, an electronic intelligence spacecraft and a demonstration flight of the Delta IV Heavy model. The Delta IV also has three firm commercial payloads, including W5.

Four versions of the Atlas V are planned and the Lockheed Martin programme has one firm payload, the US Navy's Geosat, together with six commercial launch contracts. The Atlas V's first flight in around June will be a commercial mission, carrying another Eutelsat satellite, Hot Bird 6, but its first EELV programme launch is not scheduled until 2005.

The more protracted EELV launch schedule is also causing Lockheed Martin to delay the planned US manufacture of the Russian NPO Energomash RD-180 core stage engines at Pratt & Whitney's site at Palm Beach, Florida.

While it is cheaper to use Russian-manufactured engines, the military nature of the EELV programme necessitates a US manufacturing base and that will not be ready until at least 2007.

Boeing and Lockheed Martin are well aware that maiden launch successes on what are commercial flights are vital to the future success of the Atlas V and Delta IV in the increasingly competitive international commercial arena.

Boeing's Rick Murphy, director of the Delta IV launch site, says: "You'll build a lot of confidence if your first launch is a success."


Source: Flight International