Aucbvax.1404
fa.arms-d
utzoo!duke!mhtsa!ucbvax!CAULKINS@USC-ECL
Sun May 24 12:42:54 1981
Re: Empires + Modern Weapons
In response to your message sent 23 May 1981 03:47-EDT
Excerpt from "Are We On The Verge of An Arms Race In Space"
by Richard Garwin in the May '81 Bulletin of The Atomic Scientists:
Space Based Ballistic Missile Defense
For ballistic missile defense (BMD) one must decide whether the
system is to work against an occasional ICBM, and only with some
probability, or whether it is to handle with high probability mass raids
of ICBMs. Assuming that the system is required to cover the entire
earth to counter SLBM as well as ICBM launches, and that the
orbits are circular and polar, one can determine the optimum
number of orbital planes and satellites per orbit,and the cost of the
(unopposed) system.
Thus, making very optimistic assumptions on laser technology and
assuming 400 ICBMs launched uniformly over a period of 600 seconds,
each with a vulnerable (boost) time of 250 seconds, and that
the lasers can spend 70% of their time actually illuminating
targets (30% switching between targets) - a booster hardness
of 2 kilojoules per square centimeter would correspond to a
10-year system cost of approximately $40 billion, or about
$100 million per booster destroyed. The number of satellites involved
ranges from approximately 70 at 500 kilometer altitude to about 8 at
6,000 kilometer altitude. A typical spacecraft with a 3-megawatt laser
and a 7-meter diameter mirror is assumed to have a dry mass of
3,500 kilograms and a cost of $150 million.
These performance goals are far from available. They require
an increase of laser brightness of at least a factor of
1,000,000 over what has been demonstrated in a ground-based system.
Furthermore, this calculation assumes that the laser BMD is essentially
unopposed during operation as well as during construction. Assuming
a system at the lowest orbital altitude, the average kill
range would be on the order of 2,000 kilometers.
The boosters might hide behind aluminum foil screens perhaps 100
meters square.
The satellites can be destroyed by nuclear weapons or by
anti-satellite weapons launched together with a flight of decoys
against the satellite systems. Electronic countermeasures can be used
against the satellite command and control. The BMD system
would either have to have some kind of overall control
or would have to fend for itself in selecting targets, with several
lasers choosing to illuminate some boosters and allow others to escape.
The boosters themselves by sacrificing one or two MIRVs could harden
their surfaces against laser energy by a factor of 10 or more.
As an alternative to failure the ICBM force could be launched
simultaneously, thus increasing the required cost and number of
satellites by a factor of 3 or more.The combination of booster hardening
and simultaneous launch would require at least a 10-fold increase
in laser BMD cost, without attending to the survivability of
the BMD system itself.
(end of Garwin excerpt)
Sounds to me like laser BMD systems just get us back to the same
old measure/contermeasure spiral. As I've said before, what's needed
is a solution to the meta-problem of weapons R&D.
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