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Russian military leaders have expressed concern about US plans
for a national missile defense system. Will defense technology be
limited by possibilities for a strategic imbalance? Is this just SDI
all over again?
(1722 previous messages)
- 07:01pm Mar 29, 2001 EST (#1723
>it seems you'd have to have at least twenty
>>times as much power as is required to melt a >>20cm
metal radius disc,
No problem with the 20 times. That one's a piece
>o cake. We are talking about trivial total >amounts of
I agree for mild steel. What though for carbon composites or
(very cheap!) hypereutectoid steels closer to cast iron. An
insulating layer or simple smoke screening (missile has extended
nodule ahead streaming thick smoke) could cause problems. We have to
assume cheap countermeasure aren't available before it's worth the
>assuming it were possible to correct for
missile >acceleration changes at relativistic speeds.
Relativistic speeds? 20,000 miles/hr. ain't even
Not the rocket! Relativistic speeds refers to the transfer of
position information back to the laser and the beam back to the
rocket. I should have said: 'relativistic limited information
transfer speeds'. See next sentance.
>(ie: no lag between observations and
correction >>to transmitted beam - instantaneous
Direct on, the ICBM won't move a centimeter in
>the time it takes light to make the trip. And >ballistic
stuff is a sitting duck.
Therefore minimum lag of 10^7/(3*10^8)=3*10^-2s each way, or 60ms
Not one but thirty!
Though you're right that the sideways-distance moved by a
side-rocket firing is almost insignificant, so you're right in that
the x-component varying is easily tracked with sufficent
(So we can't use side rockets to render it theoretically
impossible, as I earlier though).
- 07:01pm Mar 29, 2001 EST (#1724
And if somebody wants to correct me -- these calculations are too
elementary to be really classified, we should arrange a meeting,
that can be videotaped, or a videoconference, that we can make
available on the net, and bring umpires -- so that the answers are
clear. These schemes are nonsense.
- 07:03pm Mar 29, 2001 EST (#1725
That might be indelicate -- no doubt I've made an impolite
suggestion. But what are the stakes here?
Shouldn't the truth be morally forcing here?
- 07:11pm Mar 29, 2001 EST (#1726
Rshowalter - I'm not sure jiving will work. The mass of the
rocket seems too large that the time delay via a targeting laser is
not sufficient to keep the laser moving across the surface fast
enough. But my estimate calcs could be wrong!
>The heat capacity of steel is relatively low,
>>but just a thin layer of material on the >>outside
of a potential future ICBM (carbon >>composite), would make
the energy required to >>destroy the missile quite
That's a wild guess. We are assuming our
>scientists are better than the North Korean >ones. Lots of
ways of defeating the mirror >coating issue.
Not that wild - most ceramics take huge heating thousands of
degrees C, and we have that technology now.
(Several times more than CERN, for example,
>uses). If the missile split into smaller >warheads, with
faster sideways accelerations, >the beam radius generated would
have increase >and the power correspondingly.
Like I said, the dern thing is traveling 20,000
>miles/hr. Material objects don't accelerate much >in the
time it takes light to make the round >trip. It would take a
brand new kind of > acceleration device.
The max. acceleration would have to be larger than I thought (see
previous post), but at some engine-mass ratio, it would be
impossible to target any point for greater than a certain period
with a certain laser radius.
>I'd be very interested if an economically
>>feasible laser plan could be created to prevent
>>relatively large numbers of (slightly altered)
>>ICBMs arriving at there targets. I'd be >>surprised
(currently), if one missile was shot >>down given the above
Are you innocent of the fact that we sold such a
>thing to Israel a few months ago? That would >explain some
This critter, built with chump change, will
>shoot down a katusha rocket at 10 km. now. Right >now. 100
km. is a piece of cake.
Yes I was 'innocent' (ignorant?) of this fact.
And this is what we know about. Entertain the
>idea that we do not tell the world the details >of our
secret weapons. Entert
I assume anything sold to Israel must be old hat unless the US
military are feeling particularly generous.
However I do remember the terribly effective Patroit missile sale
before the Gulf War to Israel, so I like to see demonstrations (or
reassurance from someone who knows - I'm happy to take your word on
it) before I believe the effectiveness of new weapons!
- 07:19pm Mar 29, 2001 EST (#1727
The Patriot effectiveness, as you may remember, was praised to
the sky for a while, and made hearts beat with pride -- but it
turned out the Patriots never hit anything.
The Israelis will lie for us.
So here we have data points on how our sociotechnical
system works -- and based on the judgement of George W. Bush and
his hand picked men, we should feel confident?
I repeat what I said in 1724, 1725.
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