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这是我第三次贴AIAA2013年10月关于此事的编辑部文章
送交者: 古宇庙 2016月04月29日23:50:53 于 [世界军事论坛] 发送悄悄话
回  答: 你否定别人吹牛给点资料可以吗? eachus 于 2016-04-29 23:39:14
Toward the end of the last century, U.S. development of large liquid-propellant
rocket engines had come to a complete standstill. As pointed out by then-NASA
Administrator Dan Goldin, the only such engine developed by the U.S. in the
previous three decades had been the space shuttle main engine (SSME).
Thus was the stage set for the introduction of Russian rocket technology.
In April 1992, the president of Russian engine developer Energomash visited
General Dynamics Space Systems Division (GDSSD), builder of the venerable
Atlas vehicle that had launched our first astronauts into orbit. He told division
president Mike Wynne that for $100,000 Energomash would design and 
develop for the Atlas a half-scale derivative of the RD-170, which was a 
1.7-million-lb-thrust liquid oxygen (Lox)-kerosene first-stage engine for Zenit
and Energia. Since Atlas 2’s three Rocketdyne MA-5A engines, with a combined
thrust of only 490,000 lb, were barely able to get the Atlas-2 off the pad, Wynne
understandably jumped at the chance to obtain access at such low cost to
Russia’s proven oxygen-rich closed-cycle technology in an engine that would
deliver 860,000 lb of thrust at 15-20% higher efficiency than the MA-5A. Thus
was born the RD-180, which first flew on an Atlas 3 in 2000. In 1997 GDSSD
successor Lockheed Martin (LM) ordered 101 RD-180s from Energomash for
about $1 billion and negotiated an exclusive agreement for U.S. sales.
But LM’s biggest customer for the subsequent Atlas 5 was the USAF, which
was not happy with relying on a Russian-built engine for half its Evolved 
Expendable Launch Vehicle fleet. So Energomash teamed with Pratt & Whitney
to create a U.S. company, RD Amross, to duplicate RD-180 production. 
However, Amross had great difficulty getting the detailed specifications for
materials and machining processes, because although the Russian documentation
was truly meticulous (each part had a ‘passport’ that accompanied it through
every step in manufacture), it was very different from U.S. practice. Moreover,
much of the detailed materials information and ‘tricks’ of the machining
processes were in the heads of the skilled Russian workmen, to which Amross
did not have access.
So although Amross remains the U.S. marketing agent for Energomash-
produced RD-180s, it never achieved the desired U.S. manufacturing capability.
Nevertheless, the RD-180’s great success (43 flawless launches on Atlas 3 and 5)
stimulated Orbital Sciences to file suit last June against United Launch Alliance,
which had inherited parent LM’s exclusivity agreement for RD-180s. Orbital
would like the RD-180 for its new Antares launcher, which currently uses a
derivative of the other mainstream Russian Lox-kerosene engine, the NK-33,
modified and currently being sold by Aerojet-Rocketdyne as the AJ-26.
But where are the U.S. engines in this now highly restricted field of 
opportunity? The only current candidates are Rocketdyne’s remodeled SSMEs
slated for the new Space Launch System and the RS-68s currently used on
Boeing’s Delta 4. But both these are fueled by liquid hydrogen, which has 
operational limitations compared with kerosene. The only new Lox-kerosene
prospects on the horizon are the current attempt by Aerojet Rocketdyne and
Dynetics to resurrect the half-century-old Apollo-era F-1, and the far-future
million-lb-thrust AJ-1E6 engine concept being promoted by Aerojet Rocketdyne
for the eventual upgrade of the yet-to-be-born SLS.
Not much of a heritage for a once-dominant U.S. technology. Could it be
because there’s only one U.S. liquid-propellant rocket company left?
Jerry Grey
Editor-at-Large
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