Its been proven to be pretty damned hard to hit a bullet with a bullet. Why not hit a bullet with a nuke?

I'm being serious here. We have to assume that the incoming missile carries with it a weapon of mass destruction that would kill 100,000s or millions. Would it then be worth firing a nuclear bomb of even high yeild to intercept it.

If done at a lengthy distance from the ground, or a populated area, I don't believe fallout or the blast effect would be a major problem. Even if fallout did spread, it would be less deadly than a nuclear ICBM striking a major city.

I believe there was a experiemental system deployed by Nixon, but scraped immediately, that was going to use nuclear weapons to destroy missiles. I'm assuming it died because of the ABM treaty with the USSR.

Is this a good idea?

Yes, that's why the Soviet 'Galosh' system has had nuclear interceptors for 30 odd years.

the first star wars systems proposals did just that (fight fire with fire) but people did not like the idea of nukes going off in LEO space any more then on land so it was rejected. Then they came up with anit-missle warheads and after decades of testing the success rate is still not above 50% and is useless against easy to implement decoy system (such as chafe and mylar balloons release by the missile with the nuclear warhead. The most recent ideas is to have laser turreted airplanes shoot down the rocket before they enter suborbital course and crash right back were they came from. The latter I think is the best idea.

The US had an Anti Missile Shield in the Dakota's Protecting thier nuclear stockpiles there. They eventualy got rid of them however, because they found that the EMP blasts from the anti-nuke nukes would disable all the complex computers that guide and fly the ICBM's in the silos.

The problem with using nukes as your 'bullet', is that they just need to shoot a bunch of dummy rockets, and you end up nuking people.

Originally posted by Zxanthaxzantheus
The US had an Anti Missile Shield in the Dakota's Protecting thier nuclear stockpiles there. They eventualy got rid of them however, because they found that the EMP blasts from the anti-nuke nukes would disable all the complex computers that guide and fly the ICBM's in the silos.

Not quite accurate, the ABM ws abandoned because of cost, and it's inability to deal with MIRVing warheads.

The USA has spent around $100 Billion Dollars on ABM, and so far, not managed to implement a successful system. Recent ABM tests have been mostly failures, with 'decoys' being balloons, not dummy inbounds, or MIRVs.

The Soviet Galosh system, however, worked for single inbounds, and received an upgrade to deal with limited MIRVs, although could have been easily swamped.

ABM is pie in the sky.

WellCookedFetus, I don't think lasers in the air is the answer, I think we need to deal with the sub launched nukes as they launch. I propose sharks with frikkin' lasers on their heads, .....

At the end of the day an armastice would probably be the best soloution..............alot of saved money time and resources ^_^

Originally posted by troj
At the end of the day an armastice would probably be the best soloution..............alot of saved money time and resources ^_^

Ah, but now the cold war is over, you have to worry about 'Rogue States' launching nukes!

There will always be some fork tongue from Raytheon or Lucas/TRW or whoever whispering paranoia into some jarheads ears, saying that with enough money they can make the USA safe. Well, so far $100 Billion hasn't done the job.

But, yes, adopting a foreign policy which didn't make other nations want to nuke it might be a good start!

valid point...


and the armistice would only work when humans evolve to loose all the negitive emotions such as greed/fear/anger.....

troj,

dito :)

who wants to start a rebelion state where we all live in peace and harmony........well go to.....................Denver no one goes there!!!! :D

Originally posted by Zxanthaxzantheus
The US had an Anti Missile Shield in the Dakota's Protecting thier nuclear stockpiles there. They eventualy got rid of them however, because they found that the EMP blasts from the anti-nuke nukes would disable all the complex computers that guide and fly the ICBM's in the silos. Yup. That was the LIM-29A Spartan and LIM-31 Sprint. The Spartan was a midcourse intercept vehicle that would intercept Soviet MIRVs while they were still attached to their PBV in space. The Sprint was a hypersonic (Mach 10+) missile that flew so fast it glowed red in flight. The Sprint was for point-defense against individual warheads that Spartan couldn't blot out. A two layer tiered system had a greatly increased chance of intercept because of the inherent redundancy. Both the Sprint and Spartan were part of the Safeguard system, deployed around Grand Forks AFB in Minot, North Dakota, in 1973. By 1975 they were removed from service due to cost and lack of necessity.
Originally posted by phlogistician
The USA has spent around $100 Billion Dollars on ABM, and so far, not managed to implement a successful system. Recent ABM tests have been mostly failures, with 'decoys' being balloons, not dummy inbounds, or MIRVs.

The Soviet Galosh system, however, worked for single inbounds, and received an upgrade to deal with limited MIRVs, although could have been easily swamped.

ABM is pie in the sky.Not quite. Current NMD efforts are focusing on a radically new method of intercept, so there's going to be a lot of lag with the requisite research process. Intercepting and destroying an incoming target with a closure rate close to Mach 30 is nothing to decry as anything less than miraculous. There is much expectation that the NMD program will generate a cure-all solution nearly instantaneously.

However, NMD isn't that necessary. Theater-based systems are much more mature and functional, and placed in the correct areas as they most likely will be beforehand, can easily mitigate an ICBM attack with simplistic boost phase intercept. Between THAAD, Navy Upper Tier, and the Airborne Laser, TMD will be quite functional, and quite soon.

Here's an interesting study on boost phase intercept. :

http://www.aps.org/public_affairs/popa/reports/nmd03.html

I haven't had a chance to read it yet (it's over 400 pages), but it's written by a thinktank made up of physics scientists. The report says that boost phase intercept is infeasible.

It appears to be a pretty objective paper, but I'm sure they had their own agenda when they did the study (everybody does). This report may or may not have some importantce in the future political arena.

Anyway, they have an executive summary that is just a few pages long. Give it a read if you are interested,

Sorry for taking so long to get back to this. That report looks interesting. I'll give it a look when I get time, hopefully tomorrow.

Originally posted by Stokes Pennwalt
By 1975 they were removed from service due to cost and lack of necessity.

There is much expectation that the NMD program will generate a cure-all solution nearly instantaneously.

However, NMD isn't that necessary. Theater-based systems are much more mature and functional, and placed in the correct areas

1, Safeguard was technically operational for just _one_ day. 1975 was the height of the cold war, there was still need for ABM, it's just Safeguard couldn't deliver it. Interesting how Galosh defended Moscow, and citizens, while Safeguard defended a missile base. Also interesting thet Galosh is still nominally in operation. How is the necessity different now, btw? Is it just that the threat from terrorism was oveshadowed by the Cold War, or wasn't there a threat from anybody else in the mid-70's? Or is it defense contractors using paranoia and a new 'phantom menace' to sponge of the tax payer?

2, Cure all? Nope, cure nothing! Various contractors have been attempting non-nuclear ABM since SDI. And haven't delivered much yet. It's far from instantaneous, it's grindingly slow and fruitless.

3, Boost Phase Intercept is theatre specific, which is why it won't protect against all 'rogue nations'. There could not be national coverage protecting the USA from all possible combatants, permanent presence would be needed too close to too many possible sources.

And if ABM does come to fruition in 20 years, we still have the problems of false alarms, launching against peaceful space launches, ABM launches being seen as an aggressive act by another country that the ABM will overfly, in fact, another cold war to look forward to. And then, what will happen? Long range cruise missiles will be developed, or semi-autonomous mini subs, which launch cruise missiles. ICBMs aren't the only way to deliver nukes, so you'll _never_ be safe from them.

Try diplomacy, that's a better solution.

Long range cruise missiles will be developed Already here.

Originally posted by Gifted
Already here.

Yeah, the USA already has the AGM-129 with a range of 3000km ish, but what does the 'phantom menace' have in it's arsenal?

See, Both Russia and China has GPS type systems (GLONASS and Beidou, respectively) so could easily develop a long range nuclear capable cruise missile, if they haven't already got one. So maybe a 'rogue nation' could piggy back off GPS, or one of the mentioned systems to guide a home made cruise missile. To be honest, it seems technically simpler than making ICBMs.

It is much simpler then ICBM! The problem is a cruse missile is much slower, can be detected and shot down easily. ICBMs with their speed and sub-orbital movement push the limits of modern technology to stop.

Originally posted by phlogistician
1, Safeguard was technically operational for just _one_ day. 1975 was the height of the cold war, there was still need for ABM, it's just Safeguard couldn't deliver it. Interesting how Galosh defended Moscow, and citizens, while Safeguard defended a missile base. Also interesting thet Galosh is still nominally in operation. How is the necessity different now, btw? Is it just that the threat from terrorism was oveshadowed by the Cold War, or wasn't there a threat from anybody else in the mid-70's? Or is it defense contractors using paranoia and a new 'phantom menace' to sponge of the tax payer?The thinking behind Safeguard's deployment location was that defense of the US's counterstrike capability would be a better means of deterring attack, because it would make the Soviets unsure of whether a preemptive strike could successfully mitigate American counterstrike capability. Thus, perpetuating the theory of MAD.2, Cure all? Nope, cure nothing!Neither was my point. Each ABM technology is esoteric in application and is not designed to function otherwise. This is generally poorly understood by its various punditry. Your uninformed pessimism aside, let us remember how many of NASA's early rockets exploded on the launch pad. Or how many space probes have been lost/not accomplished their missions. I think we can all probably agree that it's a good thing research wasn't abandoned after those accidents. The only test that is a failed test is a test that teaches us nothing. Research takes time and money, and lots of it. The question is not that said research is productive enough, but if it is necessary or not, which is a different debate altogether.3, Boost Phase Intercept is theatre specific, which is why it won't protect against all 'rogue nations'.You're not thinking of its deployment correctly. Let's suppose that North Korea, for instance, was suspected of being capable and willing to launch against Guam, Hawaii, or Japan. Deploying BPI TMDs to the region would place North Korea in their lateral coverage radiuses, thereby mitigating the threat for everybody - not just the CONUS. Think of it this way. TMD would protect the whole world from one threat, while NMD would protect just one nation from the world.And if ABM does come to fruition in 20 years, we still have the problems of false alarms, launching against peaceful space launches, ABM launches being seen as an aggressive act by another country that the ABM will overfly, in fact, another cold war to look forward to. And then, what will happen? Long range cruise missiles will be developed, or semi-autonomous mini subs, which launch cruise missiles. ICBMs aren't the only way to deliver nukes, so you'll _never_ be safe from them.False alarms are basically a non-issue. The current BMEWS constellation is designed simply for detecting thermal blooming of rocket engines, not type-classifying their signatures. It has neither the resolution to discern vehicle type nor the bandwidth to report it if it could. SBIRS, however, will be able to do both quite easily. Technology has come a long way since the 1970s as I'm sure you're aware. The imaging resolution of the SBIRS sensory is astounding. We're talking moving IR pictures with greater resolution than anything commercially available, for starters. Can't say much more than that though. ;)

Cruise missiles et al. are another threat that most ABMs aside from short range systems can't do much about. Typically used in attempt to prove ABM systems aren't worth the time, they're simply red herrings. There are other methods of mitigating those threats, one of which WCF already alluded to in his post above mine.Try diplomacy, that's a better solution. Indeed. But that's another argument. And I'm an engineer, not a diplomat. :)

Originally posted by phlogistician
Yeah, the USA already has the AGM-129 with a range of 3000km ish, but what does the 'phantom menace' have in it's arsenal?

See, Both Russia and China has GPS type systems (GLONASS and Beidou, respectively) so could easily develop a long range nuclear capable cruise missile, if they haven't already got one. So maybe a 'rogue nation' could piggy back off GPS, or one of the mentioned systems to guide a home made cruise missile. To be honest, it seems technically simpler than making ICBMs. It really is. The principal drawback of a cruise missile (when being considered as a supplement for an ICBM) is punctuality and survivability. Cruise missiles are slow, rarely above transsonic speeds. They take a hell of a long time to get where they're going and they're vulnerable all along the way. Always have been, really. P-51s used to chase down V-1s over the English Channel in WWII, and modern fighter aircraft can easily intercept any cruise missile in flight, provided they can acquire it. A cruise missile's greatest defense is their difficulty being spotted by air defense radar. To maximize this, missiles like the AGM-86B CALCM and RGM-109D Tomahawk use an amalgamation of GPS updates, inertial guidance, and radar TERCOM to guide themselves through lowlands as they reference preloaded topographical information in flight.

Intercontinental cruise missiles don't exist. But if they did, they'd be no more potent than subsonic bombers have been for years. In that sense, these ostensible weapons would be a regression to somewhat defunct technology, not progression.

ICBMs are infinitely more potent. They fly faster, farther, are much less vulnerable to interception, and with a larger payload capacity. The only drawback to them is their less-than-stellar (no pun intended) accuracy. Of course, when you're packing a few hundred kilotons of yield, a wide CEP isn't much to balk at anyway, I suppose.

Originally posted by WellCookedFetus
It is much simpler then ICBM! The problem is a cruse missile is much slower, can be detected and shot down easily. ICBMs with their speed and sub-orbital movement push the limits of modern technology to stop.

Yep much simpler, and more vulnerable. Just like simple, slow, vulnerable jet airliners, that were used quite sucessfully to enact terrorism recently.

In war, it's easy to draw battle lines. Peacetime, the trick is knowing where the attack is coming from. I would imagine a cruise missile attack being launched against a foreign interest, rather than domestic one, by terrorists, but that wouldn't lessen the audacity of it. A cruise missile Pearl Harbour?

Or if it was launched against the continental US, shipped as close as possible on a freighter before launch perhaps. Terrorists or 'rogue nations' have months to plan this stuff, and the good guys not long enough to react., and suspecting everybody, and being spread thin.

Stokes Pennwalt, "uninformed pessimism aside", please show me a successful test, or even recent test results. I'm having trouble locating any test data recorded in the past couple of years.

Granted, that no experiment is invalid as long as we get data, but it's not much value if we prove we can't do something. Esp after spending $100 Bn!

TMD, sounds fine, as long as you know where your attack is coming from. So that means ring fencing all suspect countries. Sounds costly, being permanently on guard for a threat that might not come to fruition.

It's about cost/benefit, and we have already seen the previous attempt mothballed, and fast. There's a saying about folks that don't learn from history, .....

phlogistician,

If terrorist were going to nuke us they do it with a nuke in the trunk of a car. It would be a lot cheaper on there part. What good would a rouge nation get out of nuking us? At best we would never know who did it, more likely we would nuke their country to oblivion.

Originally posted by phlogistician
Stokes Pennwalt, "uninformed pessimism aside", please show me a successful test, or even recent test results. I'm having trouble locating any test data recorded in the past couple of years.You mean a successful intercept of a target? That was Integrated Flight Test 9, at 23:51 GMT, October 14, 2002. IFT-9 was the last time an actual intercept has been attempted and it did succeed. There have been launches since then, but they've been of inert interceptors with various test payloads. Two days ago, there was a launch, in fact. It was a test of the new explosive bolt/shroud binder between first and second stages. As far as the overall NMD system goes, right now we're working on getting the PAVE PAWS X-band radar perfected for its construction in Shemya, Alaska, near the older Cobra Dane DEWS radar. This is for NMD.

The last successful TMD intercept was by the Navy Upper Tier, a little over a year ago, in the Kaui, Hawaii Pacific Missile Range. A SM-3 interceptor was fired from the AEGIS cruiser USS Lake Champlain, intercepting and destroying a target vehicle at about 400,000 feet over the PMRF. There was another test of the NUT system in June, but the interceptor lost control and failed to strike the target. One of the divert and attitude control thrusters in the nose of the missile didn't function correctly. In essence, the SM-3 could turn in every direction except for one, which led to a miss.TMD, sounds fine, as long as you know where your attack is coming from. So that means ring fencing all suspect countries. Sounds costly, being permanently on guard for a threat that might not come to fruition. The way it would probably work is by deploying defenses to an area where tensions were escalating and a ballistic missile threat existed. For example, North Korea being their usual pugnacious selves and trying to catalyze some sort of hostile exchange. A few NUT-capable cruisers/destroyers and airborne lasers placed off their coastline in the right areas could intercept everything from their given areas of coverage. They're suppressive systems, which means they need to be prepositioned accurately enough beforehand so that they're in place and ready when a launch comes. However, considering that a ballistic missile attack would likely follow a predictable escalation of diplomatic tension, it would be probably be possible to forecast (at least the risk) with some degree of accuracy.It's about cost/benefit, and we have already seen the previous attempt mothballed, and fast. There's a saying about folks that don't learn from history, ..... It sounds to me like you're talking about the SDI of the 1980s. It's important to remember that the purpose of SDI above all others was a political one, and that few scientists and engineers believed its fantastic and bold technologies would ever bear fruit. Most of the stuff from back then is still far beyond our capabilities even today. That by no means goes to say that the program was worthless, or taught us nothing. On the contrary, it was a huge contribution to many different scientific disciplines. But I don't know a single scientist or engineer who actually believes that the SDI was truly expected to deliver to us space based X-ray lasers and neutral particle beams. Waste of money? Maybe so. It's all a matter of perspective, and quite frankly, any money spent on any research is money well spent, in my opinion. The physical sciences are tightly latticed, and much of our progress in fusion research has come thanks to SDI's laser research.

Intercontinental cruise missiles don't exist. But if they did, they'd be no more potent than subsonic bombers have been for years. In that sense, these ostensible weapons would be a regression to somewhat defunct technology, not progression. The B-52 survived 30 years of cold war. Teh B-1, meatn to replace it, was cut. Even now it would probably be hard to stop the Buff, especially anyone besides the main players in world politics. But I digress.

WCF explained:If terrorist were going to nuke us they do it with a nuke in the trunk of a car. It would be a lot cheaper on there part. What good would a rouge nation get out of nuking us? At best we would never know who did it, more likely we would nuke their country to oblivion. This means that while they might develop the tech, they wouldn't try a sneak attack.

The airborne laser system could probably be adapted into a shuttle payload, to be used in orbit against ICBMs at this stage of flight. This would probably not work with current technology(namely the space shuttle), especially in the current political situation.

why the shuttle why not a boeing 747?
http://www.acq.osd.mil/bmdo/bmdolink/pdf/laser.pdf

Yeah, the ABL is pretty sweet! A lethality demo against an ICBM is due by 2005, but this fall it's scheduled for a test against a simple drone. This will be the first time the COIL (its laser) is fired in the air.

As for the shuttle payload suggestion, there is already the SBL project. It would be an orbiting satellite armed with a chemical laser similar to the COIL in the ABL. In outer space, there is no atmosphere to attenuate and lens the beam off target from thermal blooming, so you can propogate a high energy beam of light hundreds of miles with ease.

http://www.fas.org/spp/starwars/program/abl8.jpg

This is a good breakdown of all existing and planned missile defense systems. These are all TMDs, btw. The NMD is not pictured, and despite the Bush Administration's unfortunate conglomeration of NMD and TMD, TMD remains quite independent of NMD.

Why does SBL look just like a Fly sucer in that picture??? :eek:

I don't belive interception after boost phase is easy or effective, to easy for the enemy to make decoys.

Heh, here's a closeup rendering of the SBL:

http://www.fas.org/spp/starwars/program/martin-marietta.jpg

May or may not look similar to that in the end though, save one part: the director mirror. It's a cassegrain feed parabolic mirror with 240 moveable parasitic elements, each with a refresh rate of 100 hertz using piezoelectric actuators. It's really cool. The mirrors aren't simply mounted ON piezo actuators, the mirrors themselves ARE piezo crystals with reflective coating on one side. Not only will the mirror be pointed on the whole, but the mirror itself will actually bend in tiny increments to direct the beam and change its focal length extremely accurately 100 times per second. This is how the laser beam will be able to bathe a target hundreds of miles away for the few seconds necessary to achieve a hard kill.

You are right about midcourse intercept. It's not easy mainly due to the altitudes and lateral relative speeds involved. In boost phase, a perpendicular path is generally called for, but speeds are relatively low. In terminal intercept, collective speeds are extremely high (often beyond 20,000 miles per hour) but lateral movement is almost nil.

Decoys are indeed easy to manufacture, but only worth the trouble provided you have MIRV-capable launch vehicles. Currently, all existing and future airframes from rogue nations carry unitary payloads, so they don't have any room to carry aluminized balloons in their post-boost vehicles. Decoys don't really represent that large of a threat in the immediate future.

What you don't think they can't fit a couple dozen Mylar balloons about a meter wide (inflated) (also place the warhead in one) in their rocket’s tiny warhead compartment? Like I said very simple and very cheap. By the time the warhead can be discriminated (by its mass deceleration characteristics as it hits the air) it will be to late.

Originally posted by Stokes Pennwalt

May or may not look similar to that in the end though, save one part: the director mirror. It's a cassegrain feed parabolic mirror with 240 moveable parasitic elements,

... question, feel free not to answer if it's confidential, ...

How do you focus the laser without losing coherence and therefore, intensity? Off a perfectly flat reflecting surface, not much laser intensity is lost, from a diffuse surface nearly all is, so if you have moveable piezo mirrors, all changing the path of parts the beam slightly, how do you maintain coherence, when they all meet up?

why the shuttle why not a boeing 747? I explained that, for midcouse intercept. The idea would be to bend the Space treaties that ban wepaons in space. A more advanced space-plane-like system coul dhold a suborbital position, much like the Buffs during the Cold War, boosting into orbit to intercept the warheads, then dropping down. I think that if you actually needed it, the fact that someone was actually willing to launch such an attack would drown out objections to its use. Countermeasures such as balloon decoys are ineffective if you have a cheap enough system to saturate them, rather than try to destinguish between them.

and how would you make it cheap enough to do that?

Originally posted by Gifted
A more advanced space-plane-like system coul dhold a suborbital position, much like the Buffs during the Cold War, boosting into orbit to intercept the warheads, then dropping down.

Er, constantly roving round in a sub orbital flight path, using fuel, as you're not in orbit, travelling pretty fast, at what inclination?

You can surely only cover a limited range of launch sites/targets with this method, as you'd have to be on a fairly good intercept, and it would be a matter of being in the right place at the right time. The linked article stated a figure of 1000 satellites in a constellation for good cover, so a suborbital solution wouldn't be much different?

Originally posted by phlogistician
How do you focus the laser without losing coherence and therefore, intensity? Off a perfectly flat reflecting surface, not much laser intensity is lost, from a diffuse surface nearly all is, so if you have moveable piezo mirrors, all changing the path of parts the beam slightly, how do you maintain coherence, when they all meet up? That's a good question. The laser beam coming from the laser aperture itself has a good deal of divergence to it. The directing mirror has a converse arc that roughly equals the divergence rate, collimating the beam and eliminating divergence. That's the simple part. As for maintaining plane wavefronts and beam coherency, it really doesn't happen much. The beam coming from the laser would be fairly unfocused at any distance much different than the target focal length. If it were visible it wouldn't "look like" a typical laser beam over its entire distance. This is how it's intended to operate though. It doesn't matter how incoherent or defocused the beam is as long as it's the right shape and size when it's actually on the target.

The mathematics involved are stellar and I can't begin to explain their intricacies. It's astoundingly complex as I'm sure you can see, and powerful computers are the only reason it can even be done.

Er, constantly roving round in a sub orbital flight path, using fuel, as you're not in orbit, travelling pretty fast, at what inclination? You can get to orbit to intercept the warheads in space. This is actually not very practical considering how expensive it would be, but the scenario is this: Having weapons stationed in orbit is illegal(I'm sure someone could quote the specific treaty, or whatever). To get around this, you put it in a suborbital station, where, if a launch is detected, it can easily boost into orbit, where the vacuum gives the laser hundreds of miles in range, allowing two or three systems to cover the U.S., destroy the warheads, and return to rearm, while a replacement is scrambled. By the time someone realizes you broke the treaty, they would also realize that you intercepted a nuclear strike, and would be too mad at the agreesors(if they're still around, though an ABM system would kind of make a retaliatory nuclear strike politically impossible), and forgive you. It would be purely political, if technologically and economically practical.
and how would you make it cheap enough to do that? It varies. How much does a million lives cost? If an interceptor costs $500 million, does the people think it worth spending enough to target warheads and decoys? If a laser pulse costs $5,000, it would be easier, most likely a ABMM would be expensive enough it would be more worthwhile to research advanced sensors, or just go with the laser. The same logic applies here as chaff, flares, and decoys on fighter planes, and research into unmanned vehicles.
The laser beam coming from the laser aperture itself has a good deal of divergence to it. Educate me, last I knew, this divergence means that it's not a true laser beam.

Sub orbital station? If you aren't in orbit, flying costs you fuel, so your station would need fuel to stay up, so would have a limited flight time, so need to constantly take off and land to refuel, or have some other mechanism, and you'd need many of these craft for coverage. You haven't addressed these issues in your pipe dream.

Divergence. All laser beams diverge. So what do you mean exactly?

Originally posted by Gifted
Educate me, last I knew, this divergence means that it's not a true laser beam. Well, all a "laser beam" is, is light produced by stimulated emission. It can be monochromatic or multimode. Polarized or not, etc.

All lasers have some degree of divergence. Your average Helium-Neon lab laser has around 0.9 milliradians, which means its 0.8mm diameter beam will be around 25mm at 100 meters of distance, roughly. Collimating the beam from a lab laser with a Galilean telsescope (in reverse) can reduce the divergence by half or more, with the price of losing intensity through the optics.

The Chemical Oxygen-Iodine Laser (COIL) used in the ABL and thought of being used in the SBL actually has pretty poor divergence as it emerges from the laser aperture. I don't know what it is precisely, but it's never applied to targets without passing through direction/collimation optics first. When I said it's "fairly unfocused at any distance but the target" I don't mean to paint the picture of a wildly diverse sea of light. Supposing you could observe the laser and target from a distance of a thousand miles, you'd see a pencil of light. But the beam does change diameter on its way to the target, although infinitesimally. No laser beam is truly non-divergent. A laser's tendency to produce beams with very low divergence is more due to its internal construction and means of developing the beam. When you bounce light back and forth between two aligned mirrors many times before sending it out the aperture, it ends up very parallel, based on lasing cavity length, fidelity of mirror alignment, and the number of times the photons bounce around before bursting through the output mirror.

The beam from a weapons-class laser changes slightly over its propogational path, but generally not by much. If the targeting is right, it will be its smallest diameter at the target.

Thanks, Stokes.

Sub orbital station? If you aren't in orbit, flying costs you fuel, so your station would need fuel to stay up, so would have a limited flight time, so need to constantly take off and land to refuel, or have some other mechanism, and you'd need many of these craft for coverage. You haven't addressed these issues in your pipe dream. These limitations are covered under "technological and economical practicality."

Getting a laser intercepter into orbit cost money to, alot of money.

Originally posted by Gifted


These limitations are covered under "technological and economical practicality."

That covers it? Four words hand wave over the most important details? This is a technological feat, so at least attempt to explain what technology would be used to achieve it.

Okay.
Mounting the laser system on a "space plane" would not be difficult. The economic catch here is the cost of building enough vehicles to fill the stand-off positions, have stand-by craft ready to scramble, and enough to replace these when they go for maintenance.

Maintaining a suborbital position like this would require enormous amounts of fuel. Economics comes in as far as producing the fuel in sufficient quantities to serve, and inflight refueling at 80,000 ft going mach 7 is a technological challenge, not to mention the requirements of the tanker force, possibly bigger than the laser vehicles themselves.

Catching a launch in time for the ready vehicles to hit orbit shouldn't be too difficult, we're already building the sensor network to do so.

Happy now? or should I dive in. I'm sure with a few years of study, I can answer any question you have, but most likely, like I stated earlier, this would turn out to be impractical, making it a moot point. I thought all of this was obvious, at least to someone as knowledgable as most people in this thread(you yourself saw many points), and flet I didn't have to go into more detail.

So it's ridiculously expensive, technologically unsound, but you felt you'd mention it anyway?

Highest flying 'production' aircraft were the MiG29, and the U2, ceilings were up to 70,000ft, and ranges of a couple of thousand miles. What the diameter of the earth? 7,926miles. So these record holding aircraft, the best that could be be mass produced, couldn't manage a single whole circumnavigation. They could only patrol a limited range at a higher latitude, or capped flight plan, so intercept opportunities would be limited.

There are records set by modified specialist aircraft, like the soviet P-42, or newly produced U2R's but as you'd need many, many aircraft to make your solution work, the emphasis has to be on reproduceable technology. Information on the current state of the art U2R planes, cost, actual stats and number in service are hard to attain.

So, how about a feasible plan instead?

Taking into account the recent release which blames budget cuts for the Columbia disaster, that Bush has given a tax cut, and a massive budget deficit is looming. Focus on cost, and achievabiity.

Originally posted by phlogistician
Taking into account the recent release which blames budget cuts for the Columbia disaster, that Bush has given a tax cut, and a massive budget deficit is looming. Focus on cost, and achievabiity. Truth be told, that's probably what will be done. Personally I don't imagine we'll see any super cool exospheric laser planes (or pursuit of them) for a long time. I find it highly unlikely that space will be host to anything other than sensory satellites for missile defense purposes for quite some time. There's nothing worth speaking of in the R&D pipeline. Spaceplanes yes, lightweight weaponized lasers yes, but an amalgamation of both technologies? Not that I know of.

Spaceplanes, well, for coming back to earth at least, NASA were developing that X-thingy as an escape vehicle for the ISS, but it's taking it's time. The report on Columbia mentioned refurbishing the shuttle fleet for use for another ten or twenty years, so I think if that happens the R&D budget for it's replacement will be spread pretty thin over this time period or deferred.

Last real development work I saw toward spaceplanes were hybrid jet/rocket engines being fitted to a Tupelov by NASA to test performance. No idea if they flew one yet.