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And despite five years of exhaustive design work and ground tests, just before launch there are bound to be at least fleeting visions of cascading fireballs raining flaming rocket debris into the depths of the Atlantic Ocean.

"You can never be too cautious when youre launching a rocket. I dont care whether its the 50th [flight] or the first," said John Karas, a vice president with Lockheed Martin Space Systems Co. "You always know there are a few unknowns out there."

Added Robert Monaco, president of RD AMROSS, a joint venture U.S.-Russian company which built the Atlas 3s first-stage engine: "Lets all keep our fingers crossed."

"It really does scream out of here. Essentially, were going out of hereat double the velocity, double the acceleration that we usually do. So its going to be pretty exciting. I kind of liken it to the old Star Trek, where they say `Engage, and you see this little streak go across space."

Now standing 170 feet (51 meters) tall on complex 36 at Cape Canaveral Air Force Station, the Atlas 3 and its payload -- a European television satellite -- are scheduled to blast off between 5:37 p.m. and 7:57 p.m. Eastern Daylight Time (21:37 and 23:57 GMT).

An initial bid to launch the Atlas 3 was scrubbed Monday after a computer that runs a crucial radar tracking system on the Atlantic Ocean island of Bermuda crashed repeatedly.

Considered mandatory for launch support, the radar system tracks rockets in flight so that they can be deliberately destroyed if they careen out of control and threaten coastal of island populations. The computer that runs the system is expected to be up and operating in time for the launch attempt tonight.

An extraordinarily unique machine, the Atlas 3 is the first American rocket to be powered by a Russian-built engine and, if all goes well, look for the new booster to get out of town fast.

"It really does scream out of here. Essentially, were going out of here at double the velocity, double the acceleration that we usually do. So its going to be pretty exciting," Karas said.

"I kind of liken it to the old Star Trek, where they say 'Engage, and you see this little streak go across space."

Credit the rapid departure to an RD 180 engine built by NPO Energomash of Khimky, Russia, a company considered the premier rocket engine manufacturer in the former Soviet Union.

A key partner in the RD AMROSS venture, the company shepherded the new engine through a $100 million development program that will culminate with the Atlas 3 launch.

The powerful RD 180 is at the heart of that effort. It will enable the Atlas 3 to fly into orbit with only two engines, rather than the nine employed by Lockheed Martins Atlas 2-AS rocket.

The second Atlas 3 powerplant: A single-engine Centaur upper-stage booster made by the Pratt & Whitney division of United Technologies Corp.

Compared to the Atlas 2-AS, the new Atlas 3 will require only two -- rather than five -- in-flight stage separations, critical events that must come off without a hitch to ensure mission success.

Whats more, engineers eliminated 15,000 parts, greatly reducing the number of potential mechanical glitches that can cause multimillion-dollar mission failures. And the Atlas 3 also can be factory-assembled in a day -- rather than weeks -- which is the case with Atlas 2 rockets.

"Overall, weve improved the rocket to where we think it is one of the most reliable rockets in the world," Karas said.

The market for the new Atlas 3, however, has not exactly been brisk.

Lockheed Martins first Atlas 3 customer -- Space Systems Loral -- booked a flight for last summer but backed out of the deal when Boeings Delta 3 rocket -- which employs a similar upper-stage engine -- suffered back-to-back failures on its first two flights.

A lengthy investigation into the second of those botched launches -- which was blamed on an upper-stage engine glitch -- effectively grounded the Atlas 3, prompting Loral to fly its satellite payload on a rival Ariane 4 rocket.

All tolled, only five satellite-delivery missions have been booked on Atlas 3s. And Lockheed Martin hopes to launch 12 to 18 of the vehicles to test technologies that are key to its next-generation rocket, the Atlas 5, which is expected to debut in 2002.

"So this [launch] is very important for us -- not only for our near-term customers, but for our future customers," Karas said. "The best sales events we have are our launches, so hopefully in the future well have more sales for Atlas 3."