된 것이라는 주장입니다. 참조하시길...
*출처: http://seattlepi.nwsource.com/opinion/108569_missile14.shtml
Friday, February 14, 2003
North Korean threat exaggerated
IVAN OELRICH
SCIENTIST
CIA Director George Tenet told Congress Wednesday that North Korea
has a missile that can reach the United States, even though North
Korea has not yet demonstrated this capability.
Coupled with the crisis of Pyongyang's nuclear weapons, this has led
many to believe North Korea could strike the American West Coast
with nuclear weapons.
Yet this is not the case. Events in North Korea are indeed worrying,
but the public debate is not helped by exaggerating the threat.
Most of our information about North Korean missiles comes from
observing flight tests; so we know much about the shorter-range
missiles that the North Koreans have flown. But Pyongyang has not
tested intercontinental-range missiles. Without flight tests, U.S.
intelligence analysts can only estimate the sophistication of North
Korean technology and the calculated range of any large missile is
extremely sensitive to these estimates.
How far a missile can deliver a payload is determined by the
efficiency of the engines, the amount of fuel and the weight of the
rocket structure and payload. For any long-range rocket, fuel makes
up the great majority of the initial weight. The structure is the
great majority of the remainder and the payload is typically a tiny
fraction of the total initial weight.
Thus, small changes in the estimates of the required structural
weight of the rocket or the efficiency of the engines translate into
large changes in the mass left for payload. In general, as the range
of the rocket increases, the calculated performance becomes ever
more sensitive to these technical assumptions.
It is important to distinguish between what is known about North
Korean missiles and what is extrapolation. The North Korean short-
range SCUD has been exported and the United States almost certainly
has access to samples of the missile. The single-stage No Dong
missile has been tested and also revealed much of its capability.
The North Koreans flight tested a three-stage space launch vehicle
in August 1998. Most analysts believe the first two stages are the
equivalent of the intermediate-range Taepo-Dong 1 missile. Radar
tracking of that single test revealed the performance of the first
two stages and, with an estimate of the mass of the third stage, the
overall performance of a hypothetical two-stage version can be
calculated. (The third stage apparently failed, possibly exploded,
and the satellite payload did not reach orbit.)
The so-called Taepo-Dong 2 -- the missile that is claimed to be able
to reach America -- is even more problematic. The second stage could
be the same as the first stage of the Taepo-Dong 1, sitting atop a
new, bigger and as yet publicly unknown first stage. Until something
is flight-tested, performance of the missile will remain speculation
about what the North Koreans could build with available technology.
A total assessment of the North Korean ballistic missile threat also
requires some knowledge of the possible payloads. If the missiles
are intended as nuclear weapon-delivery vehicles, then advances in
nuclear bomb design can have as much of an effect as advances in
missile technology.
Unfortunately, the United States knows even less about North Korea's
possible nuclear weapons than it does about its missile technology.
But our government estimates that North Korea missiles can reach the
United States with a nuclear warhead assume quite sophisticated
nuclear weapon designs.
Until the North Koreans flight-test the missile, it is too early
speak with any certainty about their ability to reach the Pacific
Northwest and government officials should be more careful to qualify
their estimates of dangers facing the nation.
* Ivan Oelrich is a senior research associate with the Federation of
American Scientists.