Space News, Pg.
13, July 21, 2003
Space-Based Missile Defense: Not So Heavenly
By Theresa Hitchens
The Pentagon's Missile Defense Agency (MDA) recently admitted that it was pushing back plans to put up a space-based missile defense test bed to at least 2008. But that does not mean the agency has given up on developing orbiting interceptors for shooting down enemy missiles in their boost-phase, shortly after their launch.
MDA officials, and hawkish proponents of using space for missile defense, continue to assert that it is technically feasible to design such a system using only 300 to 600 interceptors and costing $50 billion.
A recent study by an illustrious panel of physicists begs to differ. Even though they themselves admit to using "extremely optimistic" technical parameters, the American Physical Society (APS) in a July 16 study found that a bare-minimum system would require at least 1,600 missiles. Such a limited system would be able to defend only the continental United States (not including Alaska) and be able to shoot down only one solid-fuel ICBM coming in from North Korea (the sort the Pentagon predicts Pyongyang and other countries are likely to have within 10 to 15 years).
While the study, "Report of the American Physical Society Study Group on Boost-Phase Intercept Systems for National Missile Defense: Scientific and Technical Issues," did not provide any cost analysis, doing the math is fairly simple. Average launch costs have hovered for decades at about $22,000 per kilogram. A metric ton equals 1,000 kilograms. So, this best-case scenario for space-based missile defenses would cost $44 billion just to get the interceptors into orbit.
Some experts argue that, given the volume of space launches that would be required to boost the system, launch costs could conceivably over time come down to half that per kilogram sum: $11,000. If this is true, then such a system could be put into orbit for only $22 billion.
But here's the rub: The physicists themselves
admit that the system described above is based on assumptions that are
optimistic enough to border on unrealistic. Under more realistic technical
parameters, a system to defend the continental
There is more bad news. To cover
To defend against a single shot from
Some might say that such price-tags are not
out of line for a future strategic system, given what the
Even more troubling is the fact that the
study's more realistic scenarios include assumptions that are forgiving
in the extreme. For example, these scenarios include only 30 seconds of
time for a decision to fire - the best-case analysis assumed an automatic
shot once a potential target was detected. This is highly problematic,
in that it is impossible to tell during the early boost-phase whether
what just went up was an ICBM or a space-launch vehicle carrying a satellite
(or, in the case of China, possibly astronauts). To put it mildly, it
seems unlikely that any
Furthermore, as noted above, these scenarios
all are based on essentially a one-shot (in some cases, two-shots), one-kill
architecture. This means there is no margin for error; no redundancy in
the system. If
The APS study, in its generosity, called space-based missile defense "impractical." A more realistic look at the data shows that it is wildly so.
Theresa Hitchens is vice president and
director of the Space Security Project at the Center for Defense Information,
a non-partisan think tank in
A. Samson, Research Associate Center
for Defense Information WDC
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