Jed Rothwell wrote:
[Reporting from home with the wrong return address . . .]
thomas malloy wrote:
Last night on the BBC news they reported the then breaking news
that the American missile had hit the spy satellite. I couldn't
help but smile, Parksie was wrong yet again. Long term Vortexians
will recall his attacks on the antimissile system. It was a waste
of money, a government boondoggle, it would never work. Worse, the
government was going full speed ahead building it. Well, it appears
that he was wrong.
As much as I dislike Park, in this case he is right. Even a stopped
[analog] clock is right twice a day. Anti-satellite weapons (ASAT)
were successfully demonstrated by the U.S. long ago. The first
nuclear ASAT Nike was in 1963, and a kinetic ASAT was successfully
tested in 1985. The Chinese demonstrated one recently. They are far
easier to engineer than anti-missile systems (SDI). Satellites are
easy to detect because they follow fixed orbits at relatively slow
speeds, and you can predict where they will be weeks in advance,
whereas you have only about 15 minutes to detect and stop an incoming
nuclear warhead. Satellites do not have any anti-ASAT equipment on
board. They take no evasive action -- especially this one, which was
disabled. They are far larger than incoming nuclear missiles; this
one was the size of a bus, whereas a MIRV nuclear warhead is the size
of a trashcan. U.S. 1980s ASATs were launched from an aircraft,
meaning it was a simple, small rocket, whereas an an effective
anti-ballistic missile system would be gigantic, because it would
have to stop dozens of incoming rockets.
An anti-missile system would be very easy to defeat. Countermeasures
include things like putting balloons on board the incoming missiles
that inflate and drift away from the warhead.
I have a small nit to pick here. Your main point is certainly correct
but the example you give has a problem.
Ballistic missile warheads reenter with a velocity of something like
mach 20. A "balloon" dropped from such a warhead would not "drift
away"; rather, it would do something closer to "splatter".
Furthermore, if you made its skin of adamantium and it somehow survived
the shock of hitting air at mach-a-zillion, and slowed down enough to
"drift away", it would be trivially distinguishable from the real
warhead, due to the difference in velocity of about a factor of 10,000.
Even the old Nike Hercules systems could deal with slow-moving stuff
like balloons, unless there was an unbelievably large amount of it.
Dummy warheads are a major problem but to move enough like real warheads
so that the system gets confused, they need to have a density
approaching that of a real warhead. Balloons won't do the job.
* * *
I haven't been following the list lately (bad Steve) so maybe someone
(Jones?) has already covered this, but the question of *WHY* the U.S.
chose to shoot down that satellite is an interesting one.
From an "impressive PR" point of view it seems dumb -- the U.S. has had
demonstrated ASAT capabilities for, what, a couple decades, so how will
this impress anyone? (Remember that satellite they knocked down with a
missile fired from an F-15, back around 1986 or so? As I recall it
outraged a lot of scientists, because it was *not* at the end of its
useful life at all; there were, however, rumors that the whale-tracking
techniques which were being developed using that satellite might have
been usable to track U.S. subs as well and that was the real reason for
zapping it.)
From a hysteria point of view it seems dumb -- now we'll get people all
scared of satellites which contain hydrazine, which is ubiquitous in
satellites. Just great, just what we need, more fear of legitimate
space science.
From a safety point of view it seems dumb -- the hydrazine, in a
thin-walled tank, would surely have been vaporized and denatured during
reentry; it's inconceivable that it would have posed any sort of hazard
on the ground. It burns to something fairly innocuous, so it wouldn't
have posed a threat to the upper atmosphere, either.
From a "moral high ground" point of view it seems dumb -- this will
make it a whole lot harder for the U.S. to effectively criticize other
nations for blowing stuff up in space.
In fact it seems just all-around dumb -- but we all know the U.S.
military is not all-around dumb. So why DID they shoot it down?
One theory I've run across is that it wasn't a spy satellite at all, and
it actually contained something a lot more dangerous than hydrazine. 10
kilograms of plutonium, say, for example. If *THAT* reentered in a
single chunk it might cause major trouble -- but if it could be blasted
to bits at the edge of the atmosphere, it would be dispersed over a
large enough area that nobody would notice (and nobody would get hurt).
So then, the question is, why would the military have launched an atomic
bomb into space? We've got lots of them on the ground already, complete
with very effective delivery systems. One possibility is that they
wanted to "stage" an attack on their own forces, as part of the move to
keep the ongoing "war on terror" going on.
(Whatever, the claim that the satellite was dysfunctional certainly
seems plausible.)
ASAT
proved successful, and $60 to $90 billion has been spent on the R&D
phase so far, but SDI has failed every realistic test, and there is
no telling how many tens of billions more dollars it would take to
make it work.
Perhaps, in the future, a breakthrough will make a viable SDI
possible. That's another matter.
- Jed
