Zenith Star

[Forest Green]

It's still a ridiculously complex task. Putting the stuff in orbit is only one part. Linking all the sensors together, developing a command and control system, and making sure the weapons will actually work, are all really difficult things to do.

Some people have this belief that "if only" enough money had been thrown at SDI, it could have been made to work. But there's a great counter to that. Look at the past 35 years of effort developing better missile early warning systems. It's a very complex history involving numerous starts and stops, programs canceled and delayed. One of the main components was the GEO and HEO-based infrared satellites, and they ultimately entered service a decade after they were supposed to. So from just one component of missile defense we have proof that this stuff is really hard.

Building warheads isn't cheap for the enemy though, neither are the missiles. Sure the development has taken a long times but the USSF is putting in place systems to track and target hypersonic targets, ground targets and even air targets over the next 5 years. Many feel that the metrics are now such that defence makes a cheaper deterrent than going all out on offence. Nothing will deter an enemy better than the fear that a nuclear exchange might end up being largely one-way, with that way being towards them.

 

[Byeman]

Building warheads isn't cheap for the enemy though, neither are the missiles. Sure the development has taken a long times but the USSF is putting in place systems to track and target hypersonic targets, ground targets and even air targets over the next 5 years. Many feel that the metrics are now such that defence makes a cheaper deterrent than going all out on offence. Nothing will deter an enemy better than the fear that a nuclear exchange might end up being largely one-way, with that way being towards them.

Tracking is one thing, eliminating is another. Still easier saturate the target area.

 

[Forest Green]

Tracking is one thing, eliminating is another. Still easier saturate the target area.

Nuclear warheads are expensive, around $100m a pop, ditto for ICBMs, and if you kill the ICBM pre-warhead release, saturation will be difficult and expensive for any enemy to achieve and with a layered system they have the quandry of how many warheads and missiles are required for a single target, which complicates planning and makes the enemy's nuclear deterrent prohibitively expensive.

 

[blackstar]

There are already examples from Ukraine, and apparently also from Israel, that the defenders are running out of missiles faster than the attackers are running out of offensive missiles. And with a nuke, the balance favors the attacker much more, because a few nukes getting through causes tremendous damage.

But we're mixing up many different issues here: SDIO/historical systems, current systems, future systems, strategic and tactical.

 

[Byeman]

Nuclear warheads are expensive, around $100m a pop, ditto for ICBMs, and if you kill the ICBM pre-warhead release, saturation will be difficult and expensive for any enemy to achieve and with a layered system they have the quandry of how many warheads and missiles are required for a single target, which complicates planning and makes the enemy's nuclear deterrent prohibitively expensive.

Quite the opposite. How many defensive missiles for each offensive warhead. Many defensive missiles won't even be able to engage a target.

 

[Forest Green]

Quite the opposite. How many defensive missiles for each offensive warhead. Many defensive missiles won't even be able to engage a target.

We're discussing space-based systems here. A 1s blast from a 2MW laser takes out the booster section on an R-36/SS-18 in this scenario, 10 warheads down. Or alternatively a Brilliant Pebbles or Garage launched KKV takes out the missile just as it leaves the atmosphere - 10 warheads down. There was also talk of a space-based particle beam in recent years.

With a space-based primary layer, ground-launched missiles or THAAD 6.0 (https://www.secretprojects.co.uk/threads/thaad-development.18894/post-754109) would only be there for the strays that the space system allows through.

 

[Scott Kenny]

The H and F were likely stored separately as per this process for DF, which gives atmospheric penetration down to lower altitudes.

Hydrogen fluoride laser - Wikipedia

en.wikipedia.org

HF gas is the waste product.

 

[Firefinder]

Plu

HF gas is the waste product.

Luckly the EPA does not exist in SPACE...

And I pretty sure venting it was part of the cooling process.

 

[Scott Kenny]

And I pretty sure venting [HF gas] was part of the cooling process.

It was, but you still need a reaction chamber and exhaust route that can handle extremely hot HF gas. Plus it's going to potentially linger around the outside of the satellite.

I mean, a 10 megawatt chemical laser is dumping about 90 megawatts of heat, most of that in the HF gas exhaust.

 

[Forest Green]

HF gas is the waste product.

Correct, I imagine it's expelled sharpish.

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/chemical-laser

I mean, a 10 megawatt chemical laser is dumping about 90 megawatts of heat, most of that in the HF gas exhaust.

It was 2MW IIRC, so 18MW exhaust assuming 10% efficiency and the use period would be very time limited, so it's a bit like the case of the gun in the first linear implosion A-Bomb if you've watched the Manhattan series, it did not have to be built to artillery standards.

 

[publiusr]

A space based laser might be effective against ground targets if enough convection is in the area:

https://www.smithsonianmag.com/smart-news/scientists-guide-lightning-bolts-with-lasers-for-the-first-time-180981462/

The space-based laser issues forth a beam just above an over-shooting cloud-top:

Overshooting top - Wikipedia

en.wikipedia.org

This also allows plausible deniability in that it is a lightning strike that does the real damage.

 

[C0de.R.E.A.M.]

Scaling a space-based laser fleet to real-world nuclear warfare is exactly why SDI struggled- between the number of targets, fuel logistics, and maintenance, it becomes an infrastructure problem as much as a technological one. Even if each laser system performed flawlessly (which is a big 'if'), the sheer number of assets needed for full coverage, not to mention the cost of keeping them fueled and operational, makes it seem like an unsustainable arms race.

But I think what makes this interesting is how different the conversation would be if modern launch systems had existed back then. If we’d had something like Starship or even Falcon Heavy decades ago, could SDI have actually been deployed at scale? Or was the laser tech itself still the biggest bottleneck?

The Big Dumb Booster concepts from around that era (referencing the discussion and comments on (https://up-ship.com/blog/?p=24343) and possibly the Advanced Launch System (ALS) or the Shuttle-derived HLV proposals were likely meant for heavy polar orbit payloads, but got scrapped when Cold War priorities shifted. If a launcher like that had been funded and operationalized, maybe Zenith Star wouldn’t have looked quite so impossible from a logistics standpoint. And also, if launch was less of a constraint, was laser tech still the limiting factor?

 

[Scott Kenny]

Or was the laser tech itself still the biggest bottleneck?

I'd say that laser tech itself was still the biggest bottleneck.

Deuterium-Fluoride lasers have Deuterium fuel that likes to leak out straight through solid metal, and Fluorine that is probably the single most corrosive element known to man.

Keeping those two elements inside the tanks long term would be a monumental challenge.

 

[publiusr]

Still--those technologies may have a civilian use--as in Breakthrough Starship.

I have always been of the opinion that mil-tech that can also have peaceful uses should be pursued.

 

[Forest Green]

A space based laser might be effective against ground targets if enough convection is in the area:

https://www.smithsonianmag.com/smart-news/scientists-guide-lightning-bolts-with-lasers-for-the-first-time-180981462/

The space-based laser issues forth a beam just above an over-shooting cloud-top:

Overshooting top - Wikipedia

en.wikipedia.org

This also allows plausible deniability in that it is a lightning strike that does the real damage.

You would need to use DF (Deuterium Fluoride) instead of HF for atmospheric penetration though.

Scaling a space-based laser fleet to real-world nuclear warfare is exactly why SDI struggled- between the number of targets, fuel logistics, and maintenance, it becomes an infrastructure problem as much as a technological one. Even if each laser system performed flawlessly (which is a big 'if'), the sheer number of assets needed for full coverage, not to mention the cost of keeping them fueled and operational, makes it seem like an unsustainable arms race.

But I think what makes this interesting is how different the conversation would be if modern launch systems had existed back then. If we’d had something like Starship or even Falcon Heavy decades ago, could SDI have actually been deployed at scale? Or was the laser tech itself still the biggest bottleneck?

The Big Dumb Booster concepts from around that era (referencing the discussion and comments on (https://up-ship.com/blog/?p=24343) and possibly the Advanced Launch System (ALS) or the Shuttle-derived HLV proposals were likely meant for heavy polar orbit payloads, but got scrapped when Cold War priorities shifted. If a launcher like that had been funded and operationalized, maybe Zenith Star wouldn’t have looked quite so impossible from a logistics standpoint. And also, if launch was less of a constraint, was laser tech still the limiting factor?

Cost per kg to orbit was a major factor. It cost $30,000/kg even 20 years ago but it's now just $500/kg. In real terms this means that for the price of launching just 1 asset 20 years ago, you could launch 60 today.

I'd say that laser tech itself was still the biggest bottleneck.

Deuterium-Fluoride lasers have Deuterium fuel that likes to leak out straight through solid metal, and Fluorine that is probably the single most corrosive element known to man.

Keeping those two elements inside the tanks long term would be a monumental challenge.

It was mainly the fact they didn't even have a launcher capable of putting up 40t back them. They were working on one, but otherwise, Zenith Star would have had to be launched in two pieces and assembled in orbit. Was Zenith Star DF or HF anyway?

 

[blackstar]

But I think what makes this interesting is how different the conversation would be if modern launch systems had existed back then.

It is very easy to fall into the trap of "if we can make launch cheap enough, then everything else is simple."

You want to know what the hidden killer is for most weapons systems? Software. It's easy to think in terms of big pieces of hardware, but writing millions of lines of code for a highly complex system of systems that has to work right the very first time it is used would be the biggest problem.

 

[Forest Green]

It is very easy to fall into the trap of "if we can make launch cheap enough, then everything else is simple."

You want to know what the hidden killer is for most weapons systems? Software. It's easy to think in terms of big pieces of hardware, but writing millions of lines of code for a highly complex system of systems that has to work right the very first time it is used would be the biggest problem.

I imagine that the largest problem in the 1980s would actually have been running the code fast enough but that's another problem that technology advancements since have overcame. Higher level programming languages with huge built-in libraries probably also make the task of writing the code easier, producing thousands of lines of code from a single instruction. The downside is that they typically make debugging the code harder in my experience.

 

[Scott Kenny]

It was mainly the fact they didn't even have a launcher capable of putting up 40t back them. They were working on one, but otherwise, Zenith Star would have had to be launched in two pieces and assembled in orbit.

Not a problem to assemble in orbit, the US had demonstrated that more than 20 years earlier. During Apollo. And again with Space Station Freedom/ISS.

Was Zenith Star DF or HF anyway?

IIRC DF.

 

[Forest Green]

Not a problem to assemble in orbit, the US had demonstrated that more than 20 years earlier. During Apollo. And again with Space Station Freedom/ISS.

But having to do that for dozens of craft is something different. Plus if we multiply launch costs from 20 years ago by 40,000kg per craft, it comes to $30,000/kg x 40,000kg = $1.2bn per Zenith Star (not including orbital assembly costs or RD&T + production costs). Today the launch costs would be $500/kg x 40,000kg = $20m with no orbital assembly required and I wouldn't be surprised if they could make it lighter too.

 

[Scott Kenny]

But having to do that for dozens of craft is something different. Plus if we multiply launch costs from 20 years ago by 40,000kg per craft, it comes to $30,000/kg x 40,000kg = $1.2bn per Zenith Star (not including orbital assembly costs or RD&T + production costs). Today the launch costs would be $500/kg x 40,000kg = $20m with no orbital assembly required and I wouldn't be surprised if they could make it lighter too.

If you're launching the hundreds of Zenith Stars that the program needs, you're building hundreds of rockets to launch them as well. Which will bring down the cost per kg.

Today they wouldn't even bother with a DF laser, they'd use fiber.

 

[Forest Green]

If you're launching the hundreds of Zenith Stars that the program needs, you're building hundreds of rockets to launch them as well. Which will bring down the cost per kg.

Today they wouldn't even bother with a DF laser, they'd use fiber.

Quite possibly but the 60-fold reduction in average price with RLVs is a major boon anyway. Back in the 1980s/90s the launch costs would likely have exceeded the unit price. The price and practicality environment has changed massively in the last 35 years.

As regards fibre laser, maybe, although I'm not aware of any 2MW continuous wave examples at present, nor do I know the weight of such. The most powerful CW laser is still DF AFAIK.

 

[publiusr]

I would think 3D printing would make a KKV cheaper than a warhead (no fissile needed) if not cheaper than a decoy

 

[Firefinder]

I would think 3D printing would make a KKV cheaper than a warhead (no fissile needed) if not cheaper than a decoy

As the old saying goes...

Steel is Cheap, the Electronics are not.


Its all the fiddy electronics to put that KKV onto the target.

And they need to be decent, cause missing by a centimeter has tge same impact as missing by a kilometer. None on target. Thro the tech needed has come do ALOT in the last few years, by 2010 you can get all the same gear of tge 90s design for pennies in half tge size. Even with inflation the same tech still be cheaper.


As for the laser...

How wide was the beam?

Cause a 500 kilowatt beam of a few centermeters can do the same damage as a 3 meter 5 megawattter due to putting more energy in less space.

 

[Scott Kenny]

As regards fibre laser, maybe, although I'm not aware of any 2MW continuous wave examples at present, nor do I know the weight of such. The most powerful CW laser is still DF AFAIK.

You don't want a CW laser, anyways.

 

[Forest Green]

You don't want a CW laser, anyways.

2MJ in a short pulse is likely to be tricky for a satellite-based system, likely much heavier. Such systems currently exist only in huge ICF lasers.

 

[Scott Kenny]

2MJ in a short pulse is likely to be tricky for a satellite-based system, likely much heavier. Such systems currently exist only in huge ICF lasers.

The stackable Diode and Fiber systems seem to be closing in on that.

The problem is that 2MW CW lasers take about 5sec per target to deliver enough energy to cause destruction.

 

[Forest Green]

The stackable Diode and Fiber systems seem to be closing in on that.

The problem is that 2MW CW lasers take about 5sec per target to deliver enough energy to cause destruction.

Any links?

 

[Scott Kenny]

Any links?

Book I read in Junior High about SDI. Featuring the test shots using MIRACL on a Titan missile stage under simulated flight loads and a TOW missile in flight. Both shots took about 5sec before the missile came apart.

 

[Forest Green]

Book I read in Junior High about SDI. Featuring the test shots using MIRACL on a Titan missile stage under simulated flight loads and a TOW missile in flight. Both shots took about 5sec before the missile came apart.

I meant to 2MJ fibre/diode pulse lasers.

 

[Scott Kenny]

I meant to 2MJ fibre/diode pulse lasers.

https://optics.org/news/14/11/9 Though that's a developmental contract.

More to the point, a CW laser like MIRACL needs to deliver more like 10MJ to the target to cause destruction, while a pulse laser needs far less.

 

[Forest Green]

https://optics.org/news/14/11/9 Though that's a developmental contract.

More to the point, a CW laser like MIRACL needs to deliver more like 10MJ to the target to cause destruction, while a pulse laser needs far less.

Was aware, but that is not functional yet, nor is it a pulse laser. I agree that delivering all the energy as a quick burst is better than continuous over a second, I was only questioning the current capability.

Do you have any input on this @bcredman? Are any 1-2MJ fibre/diode pulse lasers close to completion?

 

[C0de.R.E.A.M.]

I'd say that laser tech itself was still the biggest bottleneck.

Deuterium-Fluoride lasers have Deuterium fuel that likes to leak out straight through solid metal, and Fluorine that is probably the single most corrosive element known to man.

Keeping those two elements inside the tanks long term would be a monumental challenge.

For sure. That's a nightmare combo for long-term storage. Deuterium leaking straight through metal is bad enough, but then add fluorine-which reacts with almost everything - and you’re basically trying to keep a controlled chemical disaster contained in orbit.

 

[C0de.R.E.A.M.]

It is very easy to fall into the trap of "if we can make launch cheap enough, then everything else is simple."

You want to know what the hidden killer is for most weapons systems? Software. It's easy to think in terms of big pieces of hardware, but writing millions of lines of code for a highly complex system of systems that has to work right the very first time it is used would be the biggest problem.

Definitely! Good point, launch costs and big equipment chunks are just one aspect but software is really the 'glue' so to speak that makes everything work. There's no weapon system without the software anyway.

 

[C0de.R.E.A.M.]

As the old saying goes...

Steel is Cheap, the Electronics are not.


Its all the fiddy electronics to put that KKV onto the target.

And they need to be decent, cause missing by a centimeter has tge same impact as missing by a kilometer. None on target. Thro the tech needed has come do ALOT in the last few years, by 2010 you can get all the same gear of tge 90s design for pennies in half tge size. Even with inflation the same tech still be cheaper.


As for the laser...

How wide was the beam?

Cause a 500 kilowatt beam of a few centermeters can do the same damage as a 3 meter 5 megawattter due to putting more energy in less space.

Agreed! Thankfully sensor tech has shrunk in size quite a bit in the last few decades and subsequenty in cost (in some instances at least) which may suggest mass producability of KKVs at some point.

Just thinking out loud here about beam widths, a focused 500 kW beam with a small spot size could do more localized damage than a spread-out 5 MW beam, but wouldn't atmospheric diffraction or beam jitter make maintaining a narrow spot size harder over long distances? I believe recalling that maybe being one of the major issues with the Airborne Laser program (ABL) back in the day if I'm not mistaken.

 

[C0de.R.E.A.M.]

Still--those technologies may have a civilian use--as in Breakthrough Starship.

I have always been of the opinion that mil-tech that can also have peaceful uses should be pursued.

GPS is a great example as well!

 

[Firefinder]

Just thinking out loud here about beam widths, a focused 500 kW beam with a small spot size could do more localized damage than a spread-out 5 MW beam, but wouldn't atmospheric diffraction or beam jitter make maintaining a narrow spot size harder over long distances? I believe recalling that maybe being one of the major issues with the Airborne Laser program (ABL) back in the day if I'm not mistaken

If most of the beam length was in Atmo yes.

How ever these things be in Mid Earth Orbits and for 90 percent of the travel be in space uneffected by that. Add in that not only can use use the... Turret larger size to better hold the beam on target but can now pulse it to do mechicanal damage results in more usefulness.

Plus with how RVs are built, IE very tight to specs, ANY defect on the heat shield caused by the laser will likely cause it burn though and shatter like Columbia did before it explodes.

Sure it will scatter a few kilos of lightly radioactive Uranium or Platuim bits across a 100 mile plus fan blade but that is still far better then it going boom. That stuff is only an Alpha emitter and can be hand without any special gear.

 

[C0de.R.E.A.M.]

I meant to 2MJ fibre/diode pulse lasers.

I can't speak to ongoing (or any) efforts for this particular research but still an interesting read!

https://pubs.aip.org/aip/apl/article/108/13/131109/29843/High-power-cascade-diode-lasers-emitting-near-2-m

Not directly 2MJ, but this research which appears to have been funded by the U.S. Army and NSF shows significant efficiency improvements in 2μm cascade diode lasers. While this is still in the watt range, better power efficiency at these wavelengths could influence future directed energy systems. This study focuses on efficiency improvements in 2μm diode lasers, which is far below MJ-class, but the tech looks like it is improving fast.


Discussion about Lawrence Livermore's Project MARAUDER plasma railgun:

https://forums.spacebattles.com/threads/what-are-your-thoughts-on-the-project-marauder-plasma-railgun.1023062/

 

[C0de.R.E.A.M.]

If most of the beam length was in Atmo yes.

How ever these things be in Mid Earth Orbits and for 90 percent of the travel be in space uneffected by that. Add in that not only can use use the... Turret larger size to better hold the beam on target but can now pulse it to do mechicanal damage results in more usefulness.

Plus with how RVs are built, IE very tight to specs, ANY defect on the heat shield caused by the laser will likely cause it burn though and shatter like Columbia did before it explodes.

Sure it will scatter a few kilos of lightly radioactive Uranium or Platuim bits across a 100 mile plus fan blade but that is still far better then it going boom. That stuff is only an Alpha emitter and can be hand without any special gear.

That makes sense about MEO reducing atmospheric distortion given that most of the beam’s travel would be in space anyway, so that issue wouldn't be as bad as it was with ABL. The turret size helping with beam stabilization is an interesting point too.

I hadn’t really thought about pulsing for mechanical damage rather than just heating, kind of a ‘brute force’ approach to bypassing the need for a full burn-through. If even minor heat shield defects could lead to catastrophic failure like Columbia, then the laser wouldn’t need to cut all the way through, just weaken a critical area.

But how much precision would be needed to ensure the beam hits the right spot? RVs are moving fast and could have last-second maneuvering. Wouldn’t that make consistently hitting a vulnerable section tricky, even with modern tracking?

 

[Firefinder]

But how much precision would be needed to ensure the beam hits the right spot? RVs are moving fast and could have last-second maneuvering. Wouldn’t that make consistently hitting a vulnerable section tricky, even with modern tracking?

On an RV said vulnerable area is basically anywhere on the front third to half of the vehicle. Is part of the heatshield? Thats where you want to hit.

And it be target in the none manveuring boost and "cruise" stage of bout like...

10 to 20 minutes depending on Launch to Target range and the like. The thing going to be either going straight up on a rocket or difting in space where it cannot maneuver at all, or at least fast enough to dodge a freaking laser. Like these Laser Sats be ABOVE the highest where RVs can go, and be shotting down basically at light speed. Theres not much manveuring you can do to dodge that. Throw in it likely only need a few seconds at most to do enough damage to either cause it to break up or better, cook off the explosives?

Since the Soviets did not use insentive explosives in their nukes at all, meaning its not impossible to cause the bomb to go up in a 2000 pound explosion cause the timing is going to be none existing and timing the explosion is the biggest issue in making sure Nukes make the BIG BOOM.

So basically well within semi modern targeting abilities.

Last Second Maneuvering is only useful in the Terminal Phase and it been shown to still be targetable.

 

[Byeman]

I hadn’t really thought about pulsing for mechanical damage rather than just heating, kind of a ‘brute force’ approach to bypassing the need for a full burn-through. If even minor heat shield defects could lead to catastrophic failure like Columbia, then the laser wouldn’t need to cut all the way through, just weaken a critical area.

they are more robust than the shuttle. They would survive longer than any part of theICBM.