WASHINGTON -- When the first Atlas III with a telecommunications satellite payload finally lifts off from Cape Canaveral later this summer, the roar of the veteran U.S. space booster will in fact be the sound of a new era in space.

For the first time in U.S. space history an American space vehicle will be launched powered by Russian rocket engines. The combination of the Russian engines and the veteran U.S. booster design will make for a more competitive commercial ride into orbit, or so the rocket's builder, Lockheed Martin, predicts.

The Atlas III has been delayed indefinately by gremlins in the vehicle's subsystems, although company officials are still hoping for a late summer takeoff. Riding along with the Telestar satellite payload will be the future of the company's space launch business, as well as that of a subsidiary, International Launch Services. The rockets are built by Lockheed in Denver, Colorado and sold by ILS in San Diego, California. The Russian engine that will power the Atlas III is itself a veteran of the old Soviet space program. The engines powered the Soviet military Zenit booster and the large Energia carrier rocket for the discontinued Buran Soviet space shuttles.

Called the RD-180, the rocket engine will increase the Atlas lifting ability to more than 9,000 pounds, and in more advanced Atlas V designs to more than 13,000 pounds to geostationary orbit. At that range the world's fleets of communications satellites are in a high Earth orbit

that allows their use for telephone, cable, video, and other communications services. Use of the Russian engines boost the veteran rocket's lifting ability by nearly a third.

Lockheed Martin, builder of the Atlas vehicles, are buying the RD-180 units from a consortium that includes Pratt and Whitney and the engine's maker, NPO Energomash. That same Russian design firm builds the Soyuz and other space rockets once the mainstay of the Soviet space fleet. Now the rockets and their engines are looked upon as commercial commodities, to be sold to any perspective customer with a satellite or payload.

The RD-180 uses the same fuel as the previous Atlas engine, theU.S.-made MA-5A built by the Boeing Rocketdyne unit. But the Russian powerplant is throtteable, which means it can be more fuel efficient and subject its satellite payloads to a gentler ride into space. With the new unit, a stage-and-a-half design used on the Atlas for more than 30 years can be eliminated, making the rocket more efficient and hence cheaper and more competitive.

Lockheed Martin also chose the RD-180 for their new military throw-away rocket, the Air Force Evolved Expendable Launch Vehicle due to enter service in 2001.

The engine units will be assembled in the U.S. at a Pratt and Whitney plant in Florida. Eventually RD-180 engines will be built in the U.S. under Russian technical supervision.

By use of a prime asset of an old Cold war adversary, the U.S. commercial launch business will get a new lift for space- literally.