Re: Air Force Turns 747 Into Holster for Giant Laser

2001-07-26 Thread Steve Schear

At 04:43 PM 7/24/2001 -0500, Jim Choate wrote:
On Tue, 24 Jul 2001, Eugene Leitl wrote:

  On Mon, 23 Jul 2001, Jim Choate wrote:
 
   Maybe. But even mirrors can be burned through by a laser. And then we've
 
  Jim, why are you trying so hard to make a complete fool out of yourself,
  in a public forum?
 
  A chemical laser needs active optics to track your remote target. What do
  you think that optics is made from, unobtainium? Do you understand basic
  laws of optics? I recommend purchasing a 15 W laser (and a pair of
  matching protection goggles), and then use it to ignite a match from a
  close distance, and then over a few km, preferably during summer in your
  native Texas. You could target the beam towards a projection wall, and
  watch it with a pair of binoculars. It will be quite instructive.

The optics used for focusing are NOT mirrors, they are (hopefully)
transparent at the frequency under use. A mirror on the other hand is
required to be OPAQUE with respect to transmission, we want full, 100%,
reflectivity. That means that every photon that hits that mirror
interacts, loses some energy, and gets re-emitted.

The optics used for focusing are probably mirrors, one fully reflective and 
probably backed by piezo actuators to controllably distort for focus and 
adjust for atmospheric distortions, the other mostly reflecting (to keep 
the lasing process going) to leak the lethal beam.

steve





Re: Air Force Turns 747 Into Holster for Giant Laser (washing tonpost.com)

2001-07-26 Thread Trei, Peter

Bill Stewart writes:

 Meanwhile of course, any foreign terrorist that wants to nuke the US
 with a physically small weapon only needs to pack it in cocaine
 and bring it in with the regular shipments, 
 while Rogue Nations that can only make large Fat Boy style weapons
 need cruder methods, like bribing a crane operator to load the wrong
 container on a ship bound for New York or Los Angelese harbor.
 
 
It may not be that easy. My understanding (based on various TV programs
broadcast back in the early 90's) is that there is a program called 'NEST',
which stands for something like Nuclear Emergency (mumble) Team,
tasked with dealing with this type of problem.

One protection hinted is that strategically chosen points of transit
(bridges, 
ports, tunnels, major highways, mail, baggage and freight facilities, etc)
have
detectors for nuclear materials. 

The thing is, while you can sheild a source to the point where it is not
a hazard, sheilding it to the point of *undetectability* is far harder task.

If you detect even a single gamma ray of a certain frequency, or 
betas or even alphas of certain energies, you *know* that a certain
isotope produced them. If the detectors note the presence of a 
certain isotopes, they generate the appropriate alarms.

There are also other detection systems - I've seen X-rays of entire
container trucks which were passing through the Chunnel - illegal 
immigrants were quite visible inside the container. 

An attacker's best chance would be to place his weapon in a
container, heavily sheilded, and then to bury that in the middle of
a stack of other containers of heavy shielding in the hold of a
container ship, and plan to detonate it while still on board in a
target harbor.

UPS probably would not work (besides, I think they have a 
limit of around 90 lbs). 

Peter Trei




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-26 Thread Eugene Leitl

On Wed, 25 Jul 2001, Steve Schear wrote:

 Or reduce the effectiveness of the detection system by clandestinely
 salting vessels entering our ports with radio active dust with the
 same energy signatures.  Sort of a radio active chaff.

The point of a clandestine WOMD attack is that there is no forewarning.
Salting random vehicles will make some people way more paranoid that they
already are.

As to nukes, according to anecdotal evidence (a single former employee),
UPS doesn't screen for fissible signatures. I very much doubt they screen
for vanilla HE (which, unless well packaged, emanate telltale volatiles,
and contain a high nitrogen concentration, which you could probably detect
with proper activation spectrocopy, unless *very* well shielded, or packed
with a shipment of nitrate fertilizer). Screening devices are expensive,
and have a limited processvity -- but technology marches on, of course.

If a country would want to nuke a country with few 10..100 devices, it
will get them into the country, and there's jack you can do about that.
The probability of detection would be very, very low.

The reason it's not being done is 1) no point 2) basic milk of human
kindness.

Sooner or later some random ijit or random group of ijits is going to
fry/poison/infect a few people, which will have some serious impact on
security policy, and the style of living where people concentrate.

I hope I'm not there when it happens.




Re: CDR: Re: Air Force Turns 747 Into Holster for Giant Laser (washing tonpost.com)

2001-07-26 Thread Jim Choate


Tomorrow's Soldier
David Alexander
ISBN 0-380-79502-7
Chpt. 8 War Beyond Tomorrow

On Wed, 25 Jul 2001, Trei, Peter wrote:

 It may not be that easy. My understanding (based on various TV programs
 broadcast back in the early 90's) is that there is a program called 'NEST',
 which stands for something like Nuclear Emergency (mumble) Team,
 tasked with dealing with this type of problem.
 
 One protection hinted is that strategically chosen points of transit
 (bridges, 
 ports, tunnels, major highways, mail, baggage and freight facilities, etc)
 have
 detectors for nuclear materials. 
 
 The thing is, while you can sheild a source to the point where it is not
 a hazard, sheilding it to the point of *undetectability* is far harder task.
 
 If you detect even a single gamma ray of a certain frequency, or 
 betas or even alphas of certain energies, you *know* that a certain
 isotope produced them. If the detectors note the presence of a 
 certain isotopes, they generate the appropriate alarms.
 
 There are also other detection systems - I've seen X-rays of entire
 container trucks which were passing through the Chunnel - illegal 
 immigrants were quite visible inside the container. 
 
 An attacker's best chance would be to place his weapon in a
 container, heavily sheilded, and then to bury that in the middle of
 a stack of other containers of heavy shielding in the hold of a
 container ship, and plan to detonate it while still on board in a
 target harbor.
 
 UPS probably would not work (besides, I think they have a 
 limit of around 90 lbs). 


 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-





Re: Air Force Turns 747 Into Holster for Giant Laser (washing tonpost.com)

2001-07-26 Thread Steve Schear

At 11:05 AM 7/25/2001 -0400, Trei, Peter wrote:
 Bill Stewart writes:

  Meanwhile of course, any foreign terrorist that wants to nuke the US
  with a physically small weapon only needs to pack it in cocaine
  and bring it in with the regular shipments,
  while Rogue Nations that can only make large Fat Boy style weapons
  need cruder methods, like bribing a crane operator to load the wrong
  container on a ship bound for New York or Los Angelese harbor.
 
 
It may not be that easy. My understanding (based on various TV programs
broadcast back in the early 90's) is that there is a program called 'NEST',
which stands for something like Nuclear Emergency (mumble) Team,
tasked with dealing with this type of problem.

One protection hinted is that strategically chosen points of transit
(bridges,
ports, tunnels, major highways, mail, baggage and freight facilities, etc)
have
detectors for nuclear materials.

The thing is, while you can sheild a source to the point where it is not
a hazard, sheilding it to the point of *undetectability* is far harder task.

If you detect even a single gamma ray of a certain frequency, or
betas or even alphas of certain energies, you *know* that a certain
isotope produced them. If the detectors note the presence of a
certain isotopes, they generate the appropriate alarms.

There are also other detection systems - I've seen X-rays of entire
container trucks which were passing through the Chunnel - illegal
immigrants were quite visible inside the container.

An attacker's best chance would be to place his weapon in a
container, heavily sheilded, and then to bury that in the middle of
a stack of other containers of heavy shielding in the hold of a
container ship, and plan to detonate it while still on board in a
target harbor.

Or reduce the effectiveness of the detection system by clandestinely 
salting vessels entering our ports with radio active dust with the same 
energy signatures.  Sort of a radio active chaff.

steve




Re: Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-25 Thread [EMAIL PROTECTED]


 My comment was limited to radiant energy weapons. As to those, the
 critical vulnerability exists during launch and boost phase. The target is
 slow, bright, large, has fuel on board and a nonarmored hull, which (as
 other posters observed) can be weakened with enough flux.

At least one of the propaganda articles said the kill mechanism was to
make a hole in the hull near the fuel tank.   High albedo may help the
missile here as well as the warhead, though it's probably harder
to deploy decoys at launch and boost phase than re-entry.


 The demos are just that: demos. Given that a limited strike is best
 conducted with remotely operated civilian aircraft, or plain old UPS, star
 wars seems like effect of industrial lobby.

The primary purpose of demos is to create public pressure
to get increased funding, plus to remind the public that we still have a 
nuclear-war-industrial-complex that's Protecting Our Country Against Somebody,
so in case EastAsia ever becomes a credible threat to Oceania,
Our Brave Military will have the infrastructure to do something about it.

Meanwhile of course, any foreign terrorist that wants to nuke the US
with a physically small weapon only needs to pack it in cocaine
and bring it in with the regular shipments, 
while Rogue Nations that can only make large Fat Boy style weapons
need cruder methods, like bribing a crane operator to load the wrong
container on a ship bound for New York or Los Angelese harbor.


X-Authenticated-User: idiom
~~~
Thanks;
Bill Stewart [EMAIL PROTECTED]




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-25 Thread Eugene Leitl

On Mon, 23 Jul 2001, Jim Choate wrote:

 Maybe. But even mirrors can be burned through by a laser. And then we've

Jim, why are you trying so hard to make a complete fool out of yourself,
in a public forum?

A chemical laser needs active optics to track your remote target. What do
you think that optics is made from, unobtainium? Do you understand basic
laws of optics? I recommend purchasing a 15 W laser (and a pair of
matching protection goggles), and then use it to ignite a match from a
close distance, and then over a few km, preferably during summer in your
native Texas. You could target the beam towards a projection wall, and
watch it with a pair of binoculars. It will be quite instructive.

 got weight issues that this would entail. It's not like they've got a lot
 of overhead for the job. I suspect that faceting wouldn't be any more
 effective than a smoothly round body form, it could have aerodynamic
 effects as well (ie sharp corners at the facet edges - and yes they could
 be rounded - now you're moving back toward a round rocket planform).

High albedo coating of the missile is *cheap*. Powerful lasers are that
not, especially if you need to have several of them online in an area.

-- Eugen* Leitl a href=http://www.lrz.de/~ui22204/;leitl/a
__
ICBMTO  : N48 10'07'' E011 33'53'' http://www.lrz.de/~ui22204
57F9CFD3: ED90 0433 EB74 E4A9 537F CFF5 86E7 629B 57F9 CFD3




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-25 Thread Eugene Leitl

On Mon, 23 Jul 2001, Jim Choate wrote:

 Maybe. But even mirrors can be burned through by a laser. And then we've

Jim, why are you trying so hard to make a complete fool out of yourself,
in a public forum?

A chemical laser needs active optics to track your remote target. What do
you think that optics is made from, unobtainium? Do you understand basic
laws of optics? I recommend purchasing a 15 W laser (and a pair of
matching protection goggles), and then use it to ignite a match from a
close distance, and then over a few km, preferably during summer in your
native Texas. You could target the beam towards a projection wall, and
watch it with a pair of binoculars. It will be quite instructive.

 got weight issues that this would entail. It's not like they've got a lot
 of overhead for the job. I suspect that faceting wouldn't be any more
 effective than a smoothly round body form, it could have aerodynamic
 effects as well (ie sharp corners at the facet edges - and yes they could
 be rounded - now you're moving back toward a round rocket planform).

High albedo coating of the missile is *cheap*. Powerful lasers are that
not, especially if you need to have several of them online in an area.

-- Eugen* Leitl a href=http://www.lrz.de/~ui22204/;leitl/a
__
ICBMTO  : N48 10'07'' E011 33'53'' http://www.lrz.de/~ui22204
57F9CFD3: ED90 0433 EB74 E4A9 537F CFF5 86E7 629B 57F9 CFD3




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-25 Thread Jim Choate


On Tue, 24 Jul 2001, Eugene Leitl wrote:

 On Mon, 23 Jul 2001, Jim Choate wrote:
 
  Maybe. But even mirrors can be burned through by a laser. And then we've
 
 Jim, why are you trying so hard to make a complete fool out of yourself,
 in a public forum?
 
 A chemical laser needs active optics to track your remote target. What do
 you think that optics is made from, unobtainium? Do you understand basic
 laws of optics? I recommend purchasing a 15 W laser (and a pair of
 matching protection goggles), and then use it to ignite a match from a
 close distance, and then over a few km, preferably during summer in your
 native Texas. You could target the beam towards a projection wall, and
 watch it with a pair of binoculars. It will be quite instructive.

The optics used for focusing are NOT mirrors, they are (hopefully)
transparent at the frequency under use. A mirror on the other hand is
required to be OPAQUE with respect to transmission, we want full, 100%,
reflectivity. That means that every photon that hits that mirror
interacts, loses some energy, and gets re-emitted.

I have a half dozen lasers, thank you very much.


 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-






RE: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-24 Thread Eugene Leitl

On Mon, 23 Jul 2001, Trei, Peter wrote:

 With high-powered lasers, one of the important destructive mechanisms
 is blast - the outer layer of the illuminated object vaporizes, and
 flies away from the rest of the target. The reactive force of this

You're orders of magnitude away from such fluxes. You're trying to hit a
moving, rapidly accelerating (possibly flying random evasion maneuvres)
high-albedo vehicle -- through the Mach cone, through the 100 km of
atmosphere filled with clouds, haze, random fluctuations, etc.

Once it's past boost phase, it's essentially invulnerable. Chemical lasers
have a limited numbers of shots, every energy leaving the vehicle must
pass through it's optics aperture (which must be damn transparent). The
vehicle is very complicated and delicate, and expensive. Given that you
have to make many kills during few 100 s window, it doesn't appear
cost-effective.

If it's in LEO, I just launch a bucket of tungsten or depleted uranium
birdshot in countersense orbit. Given a few iterations, I can keep
surprising amounts of orbital space clean of any operable machinery.

 gives the target a hell of a kick. Kicking off strict alignment with
 it's flight path, or putting a big dent (or even better a hole) in the

If you ablate a bit of hull sufficient to change course, you've killed the
vehicle, whether solid boosters, or cryogenic fuel tanks.

 side of a missile under several G's of stress traveling at a high Mach
 number is not healthy for the missile.

 Laser's have problems though - as they heat the air the refractive
 index changes, leading to 'blooming' or beam expansion. At too high a
 power density they can also ionize the air, which makes it effectively
 opaque. Dust, haze, and clouds are also problems.

 Using *very* short pulses eliminates many of these problems.

We're not talking about a fuel pellet in the focus of a NOVA laser.




RE: Air Force Turns 747 Into Holster for Giant Laser (washingtonp ost.com)

2001-07-24 Thread Trei, Peter

With high-powered lasers, one of the important destructive mechanisms is
blast - the outer layer of the illuminated object vaporizes, and flies away
from
the rest of the target. The reactive force of this gives the target a hell
of a kick.
Kicking off strict alignment with it's flight path, or putting a big dent
(or even 
better a hole) in the side of a missile under several G's of stress
traveling at 
a high Mach number is not healthy for the missile.

Laser's have problems though - as they heat the air the refractive index
changes,
leading to 'blooming' or beam expansion. At too high a power density they
can
also ionize the air, which makes it effectively opaque. Dust, haze, and
clouds
are also problems.

Using *very* short pulses eliminates many of these problems.

Peter Trei



 --
 From: Steve Schear[SMTP:[EMAIL PROTECTED]]
 Sent: Monday, July 23, 2001 1:34 AM
 To:   [EMAIL PROTECTED]
 Subject:  Re: Air Force Turns 747 Into Holster for Giant Laser
 (washingtonpost.com)
 
 At 09:14 AM 7/22/2001 -0500, you wrote:
 Point this baby at the ground...
 
 http://washingtonpost.com/wp-dyn/articles/A27248-2001Jul20.html
 
 I wonder what the destructive mechanism is for this system?  Heat by 
 radiant absorption seems an obvious but impractical method.  If it is,
 then 
 as the article mentions there may be some inexpensive and practical 
 countermeasures to such a system, such as making the exterior of the 
 missile body into a multi-faceted mirror able to reflect both IR and radar
 
 energy (although doing the same for the nose cone might prove more 
 difficult due to aerodynamics).
 
 steve




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-24 Thread Jim Choate


On Mon, 23 Jul 2001, Eugene Leitl wrote:

 My comment was limited to radiant energy weapons.

Even that's not sufficient since lasers have been demonstrated for
mid-course assaults as well.

 As to those, the critical vulnerability exists during launch and boost 
 phase. The target is slow, bright, large, has fuel on board and a 
 nonarmored hull, which (as other posters observed) can be weakened with 
 enough flux.

All it really takes is to get it cocked a tad off senter and aerodynamic
forces will take it apart, irrespective of hull weakness.

 The warhead in transit is fast, small, silent, and very, very hard to hit
 critically (well, it is designed to withstand reentry and nuclear
 antimissile near-hits), especially if it has a high-albedo coating, and if
 it is accompanied by a cloud of decoys. Either radiant energy weapon or
 kinetic kill, you're on the losing side here.

They've certainly managed to kill enough of them in tests starting as far
back as the ASAT fighters from the 80's. The reality is that quite a lot
of research goes on in attacking the warheads while in the mid-course
phase. It's also worth mentioning that in general the individual (assuming
MRV) warheads don't usually seperate until after mid-flight. This means a
not-so-small target.

  operations, vacuum effects (rupture a fuel tank and watch that baby
  gyrate).
 
 True, but irrelevant.

Actually not, if you strike the tanks (they are typically filled with
Nitrogen to both provide strength, ala a plastic coke bottle with the top
on and off, and to help move fuel to the engines. Approximately half the
flight occurs in this phase.

  Which has been demonstrated to be extant since the mid-80's when they
  shot the first satellite down with a high altitude fighter.
 
 A missile in boost phase is not a satellite. A cloud of decoys is not a
 satellite. An armored warhead is not a satellite.

The satellite used was specifically chosen to mimic the characteristics of
a re-entry vehicle.

All I can say is google and 'anti-satellite aircraft'.


 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-





RE: Air Force Turns 747 Into Holster for Giant Laser (washingtonp ost.com)

2001-07-24 Thread Sampo Syreeni

On Mon, 23 Jul 2001, Steve Schear wrote:

I have a hard time imagining that a mirrored and faceted vehicle exterior
would provide enough absorption to enable this mechanism, otherwise the
laser's own mirrors would like destruct from the same exposure.

Not necessarily, if the beam is focused on the target but its intensity is
lower at the source. If I'm not mistaken, the 747 stuff does precisely this,
even incorporating adaptive optics to combat atmospheric distortion. But on
the whole you're probably still probably -- this does sound more like
starwars than efficient anti-missile technology.

But I also think the question Choate posed is a valid one: what happens when
the target is *not* a ballistic missile, but people, equipment and vehicles
on the ground, normal aircraft, or air-to-air missiles? One would think that
the lower velocity differentials and expected distance-to-target make aiming
much easier, and that effective counter-measures would be significantly more
difficult to erect, considering that such conventional targets have
properties very different from those of ballistic missiles (e.g. aircraft
raise questions of aerodynamics and payload efficiency, wearable materials
with albedos high enough are difficult to come up with, rotation and
aerodynamic engineering cannot be used to dissipate the heat generated by a
hit, people/cars/tanks/whathaveyou often need to be difficult to spot using
aerial and satellite imaging, and so on).

Such weapons capability could be *quite* useful, especially if the 747 can
be effectively defended against anti-aircraft missiles, and the laser has a
range and targeting capability on par with anti-ballistic missile
applications. Hits on critical infrastructure, control over a nation's
airspace, death-from-above FUD, that sort of thing.

Sampo Syreeni, aka decoy, mailto:[EMAIL PROTECTED], gsm: +358-50-5756111
student/math+cs/helsinki university, http://www.iki.fi/~decoy/front




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-24 Thread Steve Schear

At 01:28 AM 7/23/2001 -0500, you wrote:
On Sun, 22 Jul 2001, Steve Schear wrote:

  I wonder what the destructive mechanism is for this system?

There was an article in IEEE Spectrum last year (I think) on one of the
systems. The main failure mechanism is weakening of the aeroshell and due
to increased loading the missile comes apart. The same sort of thing
happened in Desert Storm with some of the Scuds that used plywood sheeting
instead of aluminum. It's one of the primary factors of their high failure
rate.

  Heat by radiant absorption seems an obvious but impractical method.

It's the one they use primarily.

Only because the rocket exterior has not been stealthed via high 
reflectivity and faceting.

steve




RE: Air Force Turns 747 Into Holster for Giant Laser (washingtonp ost.com)

2001-07-24 Thread Petro

At 1:43 AM +0300 7/24/01, Sampo Syreeni wrote:

But I also think the question Choate posed is a valid one: what happens when
the target is *not* a ballistic missile, but people, equipment and vehicles
on the ground, normal aircraft, or air-to-air missiles? One would think that
the lower velocity differentials and expected distance-to-target make aiming
much easier, and that effective counter-measures would be significantly more
difficult to erect, considering that such conventional targets have
properties very different from those of ballistic missiles (e.g. aircraft
raise questions of aerodynamics and payload efficiency, wearable materials
with albedos high enough are difficult to come up with, rotation and
aerodynamic engineering cannot be used to dissipate the heat generated by a
hit, people/cars/tanks/whathaveyou often need to be difficult to spot using
aerial and satellite imaging, and so on).

Such weapons capability could be *quite* useful, especially if the 747 can
be effectively defended against anti-aircraft missiles, and the laser has a
range and targeting capability on par with anti-ballistic missile
applications. Hits on critical infrastructure, control over a nation's
airspace, death-from-above FUD, that sort of thing.
   

IANALS (laser specialist), but I am given to understand that with
the high energy demands of these types of lasers, and the problems with
getting good energy levels through airborne dust, clouds, etc (and especially
in combat areas where dust and other airborne particles are rather common) 
make lasers less than ideal against ground or low flying targets. 

Against high flying aircraft, you may be right. 




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-24 Thread Jim Choate


On Mon, 23 Jul 2001, Steve Schear wrote:

 It's the one they use primarily.
 
 Only because the rocket exterior has not been stealthed via high 
 reflectivity and faceting.

Maybe. But even mirrors can be burned through by a laser. And then we've
got weight issues that this would entail. It's not like they've got a lot
of overhead for the job. I suspect that faceting wouldn't be any more
effective than a smoothly round body form, it could have aerodynamic
effects as well (ie sharp corners at the facet edges - and yes they could
be rounded - now you're moving back toward a round rocket planform).


 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-





Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-24 Thread Steve Schear

At 06:05 PM 7/23/2001 -0500, Jim Choate wrote:
On Mon, 23 Jul 2001, Steve Schear wrote:

  It's the one they use primarily.
 
  Only because the rocket exterior has not been stealthed via high
  reflectivity and faceting.

Maybe. But even mirrors can be burned through by a laser. And then we've
got weight issues that this would entail. It's not like they've got a lot
of overhead for the job. I suspect that faceting wouldn't be any more
effective than a smoothly round body form, it could have aerodynamic
effects as well (ie sharp corners at the facet edges - and yes they could
be rounded - now you're moving back toward a round rocket planform).

Ahhh but  faceted exterior would deny the adversary less a visual or radar 
cross section to acquire and track (yeah I know about the tail plume).

steve




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Steve Schear

At 09:14 AM 7/22/2001 -0500, you wrote:
Point this baby at the ground...

http://washingtonpost.com/wp-dyn/articles/A27248-2001Jul20.html

I wonder what the destructive mechanism is for this system?  Heat by 
radiant absorption seems an obvious but impractical method.  If it is, then 
as the article mentions there may be some inexpensive and practical 
countermeasures to such a system, such as making the exterior of the 
missile body into a multi-faceted mirror able to reflect both IR and radar 
energy (although doing the same for the nose cone might prove more 
difficult due to aerodynamics).

steve




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Jim Choate


On Sun, 22 Jul 2001, Steve Schear wrote:

 I wonder what the destructive mechanism is for this system?

There was an article in IEEE Spectrum last year (I think) on one of the
systems. The main failure mechanism is weakening of the aeroshell and due
to increased loading the missile comes apart. The same sort of thing
happened in Desert Storm with some of the Scuds that used plywood sheeting
instead of aluminum. It's one of the primary factors of their high failure
rate.

 Heat by radiant absorption seems an obvious but impractical method.

It's the one they use primarily.

 If it is, then as the article mentions there may be some inexpensive
 and practical countermeasures to such a system, such as making the exterior
 of the missile body into a multi-faceted mirror able to reflect both IR and
 radar energy (although doing the same for the nose cone might prove more 
 difficult due to aerodynamics).

While reflecting the thermal energy is a good idea, doing the same for
radar isn't since it allows more conventional systems to be used to track
the missile, contrary to the goal of delivering large quantities time on
target. Of course reflecting the IR allows one to use a 'dual component'
system whereby another missile homes in on the reflected laser (standard
IR designator sort of stuff).

Another aspect is to beam the exhaust. By creating hydrodynamic shockwaves
in the exhaust cone it should become possible to cause the engine to come
apart due to back-pressure or simply creating ancillary thrust vectors
and causing the guidance system to mis-calculate. Thrust attack like this
must take place very early in the launch or at each stage seperation.
You've probably got no more than 30-60 seconds out of a 30 minute flight
(for a ICBM that isn't sub launched, then you've got single/double stage
and about 15 minutes max).

While the current systems won't do it, it should even be possible with
high power short pulse width systems to heat the air in front of the
rocket to cause turbulence.


 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-






Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Sampo Syreeni

On Sun, 22 Jul 2001, Jim Choate wrote:

Point this baby at the ground...

http://washingtonpost.com/wp-dyn/articles/A27248-2001Jul20.html

Seen some of this before. It's sexy, especially if one thinks of the
propaganda value: it's basically death from above.

Sampo Syreeni, aka decoy, mailto:[EMAIL PROTECTED], gsm: +358-50-5756111
student/math+cs/helsinki university, http://www.iki.fi/~decoy/front




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Eugene Leitl

On Mon, 23 Jul 2001, Sampo Syreeni wrote:

 Seen some of this before. It's sexy, especially if one thinks of the
 propaganda value: it's basically death from above.

You're saying it, propaganda value. Missiles are only vulnerable during
boost phase, while they still have fuel onboard. Chemical lasers are
expensive, have limited operation time, are cranky, and laser tracking is
a nightmare. Mirroring the surface of the missile is a cheap
countermeasure, requiring orders of magnitude larger critical flux and
thus driving hardware costs at the other end.

You need serious energy flux and tracking precision to terminate a
warhead. LEO hardware might be able to do it, but not without much, much,
much lower launch costs.

-- Eugen* Leitl a href=http://www.lrz.de/~ui22204/;leitl/a
__
ICBMTO  : N48 10'07'' E011 33'53'' http://www.lrz.de/~ui22204
57F9CFD3: ED90 0433 EB74 E4A9 537F CFF5 86E7 629B 57F9 CFD3




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Eugene Leitl

On Mon, 23 Jul 2001, Jim Choate wrote:

 Bull. Missiles are vulnerable to various assaults during their entire
 flight. The aerodynamic forces during boost and terminal flight

My comment was limited to radiant energy weapons. As to those, the
critical vulnerability exists during launch and boost phase. The target is
slow, bright, large, has fuel on board and a nonarmored hull, which (as
other posters observed) can be weakened with enough flux.

The warhead in transit is fast, small, silent, and very, very hard to hit
critically (well, it is designed to withstand reentry and nuclear
antimissile near-hits), especially if it has a high-albedo coating, and if
it is accompanied by a cloud of decoys. Either radiant energy weapon or
kinetic kill, you're on the losing side here.

 operations, vacuum effects (rupture a fuel tank and watch that baby
 gyrate).

True, but irrelevant.

  You need serious energy flux and tracking precision to terminate a
  warhead.

 Which has been demonstrated to be extant since the mid-80's when they
 shot the first satellite down with a high altitude fighter.

A missile in boost phase is not a satellite. A cloud of decoys is not a
satellite. An armored warhead is not a satellite.

The problem assymetry makes star wars a very expensive proposition. Using
airborne hardware instead of LEO is a good move, but it falls orders of
magnitude short of the target.

The demos are just that: demos. Given that a limited strike is best
conducted with remotely operated civilian aircraft, or plain old UPS, star
wars seems like effect of industrial lobby.




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Eugene Leitl

On Mon, 23 Jul 2001, Jim Choate wrote:

 Bull. Missiles are vulnerable to various assaults during their entire
 flight. The aerodynamic forces during boost and terminal flight

My comment was limited to radiant energy weapons. As to those, the
critical vulnerability exists during launch and boost phase. The target is
slow, bright, large, has fuel on board and a nonarmored hull, which (as
other posters observed) can be weakened with enough flux.

The warhead in transit is fast, small, silent, and very, very hard to hit
critically (well, it is designed to withstand reentry and nuclear
antimissile near-hits), especially if it has a high-albedo coating, and if
it is accompanied by a cloud of decoys. Either radiant energy weapon or
kinetic kill, you're on the losing side here.

 operations, vacuum effects (rupture a fuel tank and watch that baby
 gyrate).

True, but irrelevant.

  You need serious energy flux and tracking precision to terminate a
  warhead.

 Which has been demonstrated to be extant since the mid-80's when they
 shot the first satellite down with a high altitude fighter.

A missile in boost phase is not a satellite. A cloud of decoys is not a
satellite. An armored warhead is not a satellite.

The problem assymetry makes star wars a very expensive proposition. Using
airborne hardware instead of LEO is a good move, but it falls orders of
magnitude short of the target.

The demos are just that: demos. Given that a limited strike is best
conducted with remotely operated civilian aircraft, or plain old UPS, star
wars seems like effect of industrial lobby.




Re: Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread D B

First post - I hope it goes out

Here's a link to the first story I saw about this
technology in TechnologyReview.

http://www.technologyreview.com/magazine/jul01/freedmanall.asp

--- David Honig [EMAIL PROTECTED] wrote:
 On Sun, 22 Jul 2001, Steve Schear wrote:
 
  I wonder what the destructive mechanism is for
 this system?
 
 There was an article in IEEE Spectrum last year (I
 think) on one of the
 systems. The main failure mechanism is weakening of
 the aeroshell and due
 to increased loading the missile comes apart. 
 
 Many missile (propellants) are pressurized;
 weakening a bit of the skin
 will cause
 it to burst.
 
 
 
  
 
 
 
 
 
 
   
 
 
 
 


__
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/




Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-23 Thread Izaac

On Sun, Jul 22, 2001 at 09:14:56AM -0500, Jim Choate wrote:
 Point this baby at the ground...
 
 http://washingtonpost.com/wp-dyn/articles/A27248-2001Jul20.html

That will result only in a very broken 747.

-- 
___ ___  .   .  ___
 \/  |\  |\ \
 _\_ /__ |-\ |-\ \__




Air Force Turns 747 Into Holster for Giant Laser (washingtonpost.com)

2001-07-22 Thread Jim Choate

Point this baby at the ground...

http://washingtonpost.com/wp-dyn/articles/A27248-2001Jul20.html

-- 

 --


Nature and Nature's laws lay hid in night:
God said, Let Tesla be, and all was light.

  B.A. Behrend

   The Armadillo Group   ,::;::-.  James Choate
   Austin, Tx   /:'/ ``::/|/  [EMAIL PROTECTED]
   www.ssz.com.',  `/( e\  512-451-7087
   -~~mm-'`-```-mm --'-