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ATLAS III LIFTS OFF WITH RUSSIAN ENGINES

Five years downstream from programme launch, after extensive development and design work and having overcome a number of hurdles posed by the US administration, the champagne corks were finally popping at International Launch Services (ILS) on 24 May. Lockheed Martin's satellite launch marketing company was celebrating the successful first flight of the new, improved performance Atlas IIIA, which at 19.10h local time took off from Cape Canaveral's historic ramp 36B and 29 minutes later released the European Eutelsat W4 communications satellite into orbit.

It was the first time in the history of spaceflight in the USA that a US booster was powered by a Russian powerplant, the high performance two-chamber RD-180. 101 of these powerful engines were purchased by the Lockheed Martin Space Systems Company (LMSSC) for around $1 billion from the engine manufacturer Energomash in 1995, since when another $300 million has been spent on design changes to the launcher and various bench tests by Pratt & Whitney.

The successful launch has emphatically vindicated the biggest ever American-Russian joint space venture, so that ILS can now look ahead with confidence to launching between 12 and 18 of these rockets with commercial payloads over the next five years. These will include the Atlas IIIB, which is to be launched later this year with a larger Centaur upper stage. Including a special insurance package for customers, each launch costs around $85 million, making ILS a serious new contender in the hotly contested market which up to now has been dominated by Arianespace and Boeing. At a procurement cost of around $10 million (approx. DM 20 million) per RD-180, the booster can be offered around 25% cheaper than was possible in the past.

The maiden flight of the new booster is also of critical importance for the launch of the next version of the Atlas. This Atlas V EELV (Evolved Expendable Launch Vehicle) is also to be equipped with the RD-180 and the Centaur upper stage of Atlas III and will make its launch debut in two years' time.

But before then there are still a few difficulties to be overcome. For example, restrictions on technology transfer and security considerations prevented the 25 Russian technicians who were present at the launch from following the progress of their engine from the mission control room at Cape Canaveral. Yet because they needed to monitor the RD-180's performance data, they had to be assigned a special room in a less security-critical area, where they received copies of the data over a data link. They were able to report proudly that the engine's continuous throttle control system reproduced in practice the values that had been previously calculated.

Barely a second before lift-off the RD-180's combustion chamber pressure was twice the level of the Rocketdyne MA-5A powerplant previously used. The booster left the launch tower with 74% of full thrust capability, five seconds later it had reached 92%, while 33 seconds later it had reverted to 64%. Finally the thrust levelled off at 87%, producing a steady acceleration of 5.5g. Thus, after only three minutes the RD-180 had attained all the flight parameters which previous models had taken five minutes to achieve. With this success under their belts, Lockheed Martin and Energomash are setting completely new quality standards for the transport of commercial satellites.

From page 55 of FLUG REVUE 8/2000