SDI Brilliant Pebbles

[Kat Tsun]

Lasers are pretty useless due to near impossibility of battle damage assessment. For "smoking-related incidents", the CIA is already doing a good enough job on the ground with plastique.

KKVs are superior to lasers for SDI, and NPBs are superior still (but worse than KKVs) since they can at least discriminate against threats and decoys by "testing" for fissiles, but threat clouds make KKVs nearly useless with anti-simulation decoys tbh. Even if the USA has very high hopes for LRDR it's unclear if it will ever actually function adequately, and it will require a pretty sizeable quantity of things that USA has trouble making on its own (semiconductor chips) from strategic materials, which are things that could be used elsewhere instead of sitting in silos at Fort Greely.

Thermonuclear Brilliant Pebbles might be the ideal, since it can handle threat clouds better than anything else, but that would require a fairly muscular and robust fissile production system. One which I don't think anyone has had since the Cold War ended.

Something like MOKV is very far from ideal since you'd need on the order of 40-50 interceptors per missile bus to ensure no leaking, but the entire US SDI network at the moment is setup to pretty much solely defend against the dizzying arsenal of...North Korea. Which entails maybe one to three ICBM launches with fairly crude ballistic decoys and chaff corridors or mylar balloons, akin to the 1970's Chevaline, I guess? It can handle that, and in the future it will be more capable against future North Korean ICBMs. It's not meant to stop a Chinese or Russian attack, obviously.

Even GPALS orbital interception layer was only abandoned when it became clear that neither Brazil nor Iran had ambitions to develop true ICBM-nuclear capability AIUI. If non-proliferation goes out the window in the coming years then the Brazilian ICBM threat might come back, though, and America has done a good-enough job developing sufficiently muscular and cheap boosters to put orbital interceptors into place if the need occurs.

 

[Forest Green]

I don't understand the point about battle damage assessment. I'd imagine that an ICBM being plugged in the rocket motor during the burn phase would provide some noticeable indicators. Ground operatives have associated risk, I would not want to be them when they are caught, assuming it is even the case.

KKVs are limited to exo-atmospheric intercepts and single use. NPBs are good but not as easy to aim.

I don't see why you would need 50 KKVs per interceptor for MOKVs

 

[Archibald]

Accronym overload. I'm fascinated by ABM and SDI, but your abuse of accronyms is killing me. KKV ? NPB ? MOKV ?

 

[Forest Green]

Accronym overload. I'm fascinated by ABM and SDI, but your abuse of accronyms is killing me. KKV ? NPB ? MOKV ?

Kinetic Kill Vehicle
Neutral Particle Beam
Multi Object Kill Vehicle

StackPath

 

[Kat Tsun]

I don't understand the point about battle damage assessment.

You have to know you've killed a reentry vehicle or missile bus to know to stop engaging it, obviously? The benefit of nuclear mines and kinetic kill vehicles is that they provide instantaneous feedback to whether or not a bus has been eliminated: it's in multiple pieces and partially disintegrated. A laser doesn't offer that outside of atmospheric interception. Even the SDIO knew this, which is why they didn't consider the laser useful for space-based intercept. The idea was to shoot down the ICBMs as they left their silos. It's incredibly silly but it was an incredibly silly time.

Making a space based interceptor that can attack the booster stack before it's separated the bus is both technically easier and likely cheaper to launch on the aggregate these days. Lasers as ABM systems should have died in the 1980's but launch costs made space-based interceptor/Brilliant Pebbles scary...back then.

Now it's not because a private company can fund launching tens of thousands of 50-150 kg satellites into orbit from internal revenue alone. It would be trivial for the US government to do the same because it has an actually functional, Soviet-style rocket factory these days.

KKVs are limited to exo-atmospheric intercepts and single use.

Making a trans-atmospheric space-based interceptor is easier than making a FEL capable of taking down an ICBM in all honesty. We already have them, after all, in the form of reentry vehicles: they transit into space and come back down. There's no reason one can't sit in a life jacket, with a propellant bus and solar panel stapled onto a backpack, and some sort of high power communications to a SBIRS-LO or space radar system.

At no point do lasers enter the equation. They are antiquated and made sense when 24-48 supersized chemical lasers, which can actually destroy an ICBM, would not be much more expensive than lofting 3,600-36,000 Brilliant Pebbles.

Spacecraft launch costs have tanked because SpaceX discovered the lost art of Soviet rocket factories, but the costs of large satellites still exists, so there's no hope for big SDI sats when a glorified cubesat swarm is easier in every way.

I don't see why you would need 50 KKVs per interceptor for MOKVs

Because there are 50 targets and you don't know which ones are warheads and which ones are decoys? That's the point. Decoys are genuinely hard to discriminate until they hit the upper atmosphere during their last minute or so of intercept and this hasn't changed.

Fort Greely has about 40 GBIs primarily to engage literally "a couple" ICBMs from North Korea at long range, which can be assumed to not use something silly like antisimulation decoys, but rather something like a chaff corridor that can be discriminated against by an S-band or X-band radar, and given the large number of bands involved the North Koreans may not have sufficient chaff to produce a thick corridor. Mylar balloons would likely be involved, which can be determined from ballistic coefficient over the course of about three to five minutes through the exosphere, using LRDR. I don't think anyone expects high powered radar jammers or more modern systems, as that's probably beyond North Korea's capability. Maybe.

Even if it is, SBIRS-LO can discriminate as well, which was part of its original job, and the Space Force may get more advanced systems in the coming decade or so than SBIRS-LO to do the job, as they seem to want to replace the highly expensive GEO systems with a much cheaper and more accurate LEO system. NGI might be able to expand that to five or six if they had the same number of them with multiple kill vehicles per.

Conversely, the A-235 Complex can stop about 8-12 ICBMs of MX/Peacekeeper type with its entire arsenal of 84 interceptors, but the Moscow Missile Defense Complex been partially disarmed IIRC with the retirement of the 51T6 and maybe partial disarmament of the 51T6. It might be able to stop about half as many warheads with just the short-range interceptors tbh, but a terminal intercept is the most reliable against sophisticated decoys anyway, and 51T6 might as well be a supersized Sprint.

America is simply making an assumption that North Korea's penaids will resemble the UK Chevaline's chaff clouds, and simple mylar simulation balloons, rather than more sophisticated Russian or US-type antisimulation penaids. This may or may not be correct (though it probably is) but it's what LRDR is built for, rather than A-235's assumption of highly capable MX-type penaids.

If America wanted a modern ABM system, one built to stop the most effective forms of ICBM attack, it would be better served building launch silos in suburbs and radars near its major cities, with eventual expansion to space-based interceptors for boost-phase interception.

 

[Byeman]

Spacecraft launch costs have tanked because SpaceX discovered the lost art of Soviet rocket factories, b

no, they haven't. They reuse their boosters.
SpaceX has nothing like this. And neither did the Soviets.

https://flic.kr/p/cWs6g1

View: https://www.flickr.com/photos/target_man_2000/7836105834

 

[Forest Green]

I don't understand the point about battle damage assessment.

You have to know you've killed a reentry vehicle or missile bus to know to stop engaging it, obviously? The benefit of nuclear mines and kinetic kill vehicles is that they provide instantaneous feedback to whether or not a bus has been eliminated: it's in multiple pieces and partially disintegrated. A laser doesn't offer that outside of atmospheric interception. Even the SDIO knew this, which is why they didn't consider the laser useful for space-based intercept. The idea was to shoot down the ICBMs as they left their silos. It's incredibly silly but it was an incredibly silly time.

Making a space based interceptor that can attack the booster stack before it's separated the bus is both technically easier and likely cheaper to launch on the aggregate these days. Lasers as ABM systems should have died in the 1980's but launch costs made space-based interceptor/Brilliant Pebbles scary...back then.

Now it's not because a private company can fund launching tens of thousands of 50-150 kg satellites into orbit from internal revenue alone. It would be trivial for the US government to do the same because it has an actually functional, Soviet-style rocket factory these days.

There are healthy assumptions that can be made. I don't know of any warhead or bus that could withstand 30MJ (7.5kg of TNT energy equivalent) focussed on a 10cm^2 spot in a second. And it certainly wouldn't survive re-entry. That said, if the beam comes out the other side, that would probably be a good indication. Or if the conventional explosive part of the warhead is detonated. Equally, you get ~5 minutes to take out a liquid propelled ICBM like Sarmat in the burn phase, where the results will be far more obvious. Using a pulsed output it's also possible to release almost the same amount of energy in a far shorter period. This can be done by using a switchable inhibitor in the laser cavity to a allow a massive population inversion to build up before light starts being amplified, then you remove the inhibitor and you get a short pulse with massive power. The engagement times are also trivial compared to kinetic kills and the aiming and guidance simpler. You could hit a warhead with dozens of 1s burst in the time it takes for one kinetic intercept. And the Pk demonstrated for kinetic intercepts isn't great either.

There's nothing silly about boost phase intercept, it's by far the best time, especially when something like a Sarmat can carry up to 16 warheads.

KKVs are limited to exo-atmospheric intercepts and single use.

Making a trans-atmospheric space-based interceptor is easier than making a FEL capable of taking down an ICBM in all honesty. We already have them, after all, in the form of reentry vehicles: they transit into space and come back down. There's no reason one can't sit in a life jacket, with a propellant bus and solar panel stapled onto a backpack, and some sort of high power communications to a SBIRS-LO or space radar system.

At no point do lasers enter the equation. They are antiquated and made sense when 24-48 supersized chemical lasers, which can actually destroy an ICBM, would not be much more expensive than lofting 3,600-36,000 Brilliant Pebbles.

Spacecraft launch costs have tanked because SpaceX discovered the lost art of Soviet rocket factories, but the costs of large satellites still exists, so there's no hope for big SDI sats when a glorified cubesat swarm is easier in every way.

Is it? I see little evidence of that, i.e. none at all. There are no exo-atmospheric KKVs that re-enter and an increasing number of HGVs.

Chemical lasers are fine but they use fuel and have limited shots. HF wasn't a great choice though due to the long wavelength and minimum altitude limit. A FEL or solid state laser could be reactor pumped giving infinite shots, and with NTP it could both shoot and chase.

I don't see why you would need 50 KKVs per interceptor for MOKVs

Because there are 50 targets and you don't know which ones are warheads and which ones are decoys? That's the point. Decoys are genuinely hard to discriminate until they hit the upper atmosphere during their last minute or so of intercept and this hasn't changed.

Fort Greely has about 40 GBIs primarily to engage literally "a couple" ICBMs from North Korea at long range, which can be assumed to not use something silly like antisimulation decoys, but rather something like a chaff corridor that can be discriminated against by an S-band or X-band radar, and given the large number of bands involved the North Koreans may not have sufficient chaff to produce a thick corridor. Mylar balloons would likely be involved, which can be determined from ballistic coefficient over the course of about three to five minutes through the exosphere, using LRDR. I don't think anyone expects high powered radar jammers or more modern systems, as that's probably beyond North Korea's capability. Maybe.

Even if it is, SBIRS-LO can discriminate as well, which was part of its original job, and the Space Force may get more advanced systems in the coming decade or so than SBIRS-LO to do the job, as they seem to want to replace the highly expensive GEO systems with a much cheaper and more accurate LEO system. NGI might be able to expand that to five or six if they had the same number of them with multiple kill vehicles per.

Conversely, the A-235 Complex can stop about 8-12 ICBMs of MX/Peacekeeper type with its entire arsenal of 84 interceptors, but the Moscow Missile Defense Complex been partially disarmed IIRC with the retirement of the 51T6 and maybe partial disarmament of the 51T6. It might be able to stop about half as many warheads with just the short-range interceptors tbh, but a terminal intercept is the most reliable against sophisticated decoys anyway, and 51T6 might as well be a supersized Sprint.

America is simply making an assumption that North Korea's penaids will resemble the UK Chevaline's chaff clouds, and simple mylar simulation balloons, rather than more sophisticated Russian or US-type antisimulation penaids. This may or may not be correct (though it probably is) but it's what LRDR is built for, rather than A-235's assumption of highly capable MX-type penaids.

If America wanted a modern ABM system, one built to stop the most effective forms of ICBM attack, it would be better served building launch silos in suburbs and radars near its major cities, with eventual expansion to space-based interceptors for boost-phase interception.

Don't know of any missiles that carry 50 realistic decoys. And lasers are great for discrimination too.

I think they're down to 68 53T6 only now.

https://www.tandfonline.com/doi/pdf/10.1080/00963402.2021.1885869?needAccess=true

Which at best can stop 68 warheads with 100% Pk, or nearly 7 MXs.

I think you're also making a false assumption that pebbles would be able to intercept literally everywhere in space, it wouldn't. A layer would have two intercept windows - one with the missile going up, the other coming down. If several missiles come up from the same places, pebbles is defeated, since there won't be sufficient pebbles in one place to stop it. A 1050nm 30MW laser kills them before they leave the troposphere.

 

[GDTI]

I've heard about a rocket craft hovering in a hangar and laser pointing an outside target as a systems/targeting demonstration, anybody have more info on this?

Why is it that in spite of questions over the years about BP technology using laser beams, Conversation fall on its backside in discussions of actual pebble size particles to ram against ICBMs
it’s like laser beams aren’t even entertained as to what BP was?