Tim Furniss/LONDON

One of four Russian-built RD-180 engines delivered to Lockheed Martin's Denver, Colorado, plant in early December is set to power the first Atlas V Evolved Expendable Launch Vehicle (EELV) in 2002. The other three engines are for Atlas IIIA models.

Engine No 9T will be installed on the first Atlas V in January, which will be shipped to launch pad 41 at Cape Canaveral in April for "pathfinder operations" work at the refurbished Titan IV complex prior to the maiden launch.

Complex 41 will use a "clean pad" approach, with the rocket and satellite stacked in a vertical integration facility and rolled on a mobile transporter to the pad a few hours before launch - a method used by Ariane 5 at Kourou, French Guiana.

Up to 101 RD-180 engines are being developed by the joint Russian-US company, RD AMROSS, operated by NPO Energomash and Pratt & Whitney, under a $1 billion contract signed in 1996. Eight RD-180 engines have now been delivered.

The engine can be throttled up and down in flight, a first for a US expendable launch vehicle. During the maiden flight of the Atlas IIIA in May, the performance of the engine "was so good it had to be throttled back to 40% to reach the designated orbit", says Eric Novotny, vice president of sales and marketing at International Launch Services, which willeventually market the Atlas V 400 and 500 series commercially.

Lockheed has also finished building the tank for the first new Centaur upper stage that will fly on the Atlas V. The cryogenic upper stage is powered by a Pratt & Whitney RL-10A-4-2 engine, an uprated version of the presentRL-10-4-1B engine used on the Atlas IIIA.

The new Common Centaur tank, 12.7m (42ft) longer than the tank of the existing Centaur stage, will provide greater performance. It will also be used on the Atlas IIIB booster which, like the Atlas V, will be able to fly single or dual Centaur engines.

The existing Atlas IIA and IIAS fleet flies Centaur stages with two RL-10A-engines each. These models are scheduled for use in seven more flights - three commercial and four for the US Government.

The IIIA is on the manifest for two commercial and four government flights, while the Atlas V will launch the US Navy's Geosat Follow On craft in 2002 and has three firm and five optional launches of Teledesic satellites.

Source: Flight International