The guidance system and computer of the Minuteman III nuclear missile
272 points by magnat 10 months ago | 175 comments- benjam47 10 months agoI live several miles from a Minuteman silo in Montana, maintained by Malmstrom Air Force Base. The underground cabling between sites is also an interesting read (https://minutemanmissile.com/hics.html). Anytime I want to dig on my property, I have to make sure it won't interfere with their pressurized cables. I have heard a story from someone that did accidentally cut a cable, and Malmstrom AFB was able to locate the break and respond rapidly. I am a volunteer firefighter, and our station has a VHS tape and a paper guide titled "Incident Guide for Missile Field Fire Response" provided to us by the DoD regarding our role in responding to fiře incidents near or at a silo. A year or so ago, we did respond to a fire near a silo, but it occurred entirely outside the security fencing. My understanding is that the personnel at the silos also have their own ability to respond to fires.
- kev009 10 months agoThe tape is probably a reponse to some infamous disasters/tragedies:
* https://en.wikipedia.org/wiki/LGM-25C_Titan_II#Mishaps
* https://en.wikipedia.org/wiki/1965_Searcy_missile_silo_fire
* https://en.wikipedia.org/wiki/1980_Damascus_Titan_missile_ex...
- JoeDaDude 10 months agoBut isn't it the case that there is typically no personnel at the silo (or Launch Facility LF) itself? Instead, the Missile wing Commanders at the Launch Control Centers (LCC) some distance away. The LCC commands some number of LFs remotely.
- benjam47 10 months agoGood question. They definitely do have launch control centers. All available information online does seem to indicate that is the case that the silos themselves are unmanned. My understanding is that there was some security on site, but that is just based on second hand stories I've heard, and may not be true.
I do see military vehicles traveling to and from the one that I am close to semi regularly, perhaps a month or so on average.
As far as fire response, they likely have their equipment for that at the control centers as well.
- plasma_beam 10 months agoGiven we are talking about nuclear missiles, I’d like to think that while unmanned and housing decades-old tech, that the sites themselves have state of the art top secret levels of security. Then again I grew up in northern VA and we all used to assume as kids that the pentagon had missiles to protect from attack, then 9/11 happens, things like Jan 6, and you lose that confidence..
- plasma_beam 10 months ago
- benjam47 10 months ago
- nonethewiser 10 months ago> Anytime I want to dig on my property, I have to make sure it won't interfere with their pressurized cables.
Sounds like a serious weak point
- cpgxiii 10 months agoThe missile silos and control facilities are connected in a sort of semi-mesh topology, so any one cable break is unlikely to cause a communications failure. There are backup launch control interfaces available via airborne platforms (specifically the E-6 today) as well.
Digging into one of the cables is going to get you a prompt and unpleasant visit from base security.
- bunabhucan 10 months agoImage showing the layout/redundancy of the communications:
https://en.m.wikipedia.org/wiki/LGM-30_Minuteman#/media/File...
There are alternate ways to launch the missiles (e.g. radio from a plane) in the event of an attack.
- preisschild 10 months agoThey have redundancy. But they obviously want to know where it happened in case it was sabotage.
- cpgxiii 10 months ago
- beerandt 10 months agoHow different is it than a standard 811 utility-locate call?
Actual change in procedure? Or just extra cheek-clinching?
- benjam47 10 months agoToday it is the same thing (part of an 811 call). In the distant past, it was a separate call.
Around 2000 land owners are affected, and anecdoctally it seems to add a few days to a 811 response (~a week instead of 2-3 days).
- benjam47 10 months ago
- kev009 10 months ago
- tempaway4575144 10 months agoThe idea behind inertial navigation is to keep track of the missile's position by constantly measuring its acceleration. By integrating the acceleration, you get the velocity. And by integrating the velocity, you get the position.
This sounds like it couldn't possibly work (surely all the little errors compound?) but apparently it's how Apollo navigated
https://wehackthemoon.com/tech/inertial-measurement-unit-mec...
- kevin_thibedeau 10 months agoThat is how all self-guided weapons systems worked before GPS was viable. Many still retain that capability as a fallback. Notably, the Tomahawks fired during Desert Storm had to transit over Iranian airspace because they needed the mountainous terrain to correct for their inertial drift before turning toward their targets over the flat Iraqi plains.
- flavius29663 10 months ago> before GPS was viable
GPS can be jammed (see Russia-UKraine war), so inertial systems are still very important for rockets, for example some HIMARS rockets start with GPS and then rely only on inertial while getting close to target.
- missedthecue 10 months agoHimars relies on inertial navigation the entire flight and uses GPS updates to course correct. If the GPS is blocked for a sufficient amount of flightime, even with the intertial navigation, the accuracy can become unusably low.
This is how the Russians have been throwing double digit percentages of launches off course.
- missedthecue 10 months ago
- lupusreal 10 months agoAlmost all. Walleye television-guided glide bombs used edge detection on a television signal to aim themselves in. A human would designate a target at the start but then the bomb would autonomously track the target. An optical fire-and-forget system developed in the 1960s.
Sidewinders are another example. Both developed at China Lake.
- flavius29663 10 months ago
- ddalex 10 months agoWhen Nintendo Wii motes first appeared, they were some of the few devices at the time with cheap MESM accelerometers and gyroscopes that were programmer-friendly.
I remember taping two together back to back and integrating acceleration across them. That's when I learned Kalman filters. It was accurate enough so I could throw it across my desk and measure the desk length :)
- djmips 10 months agoKalman filters were also used in the AGC - useful for landing on the moon. I suspect they were not used by the Minuteman - does anyone know?
https://en.wikipedia.org/wiki/Kalman_filter#History
https://github.com/chrislgarry/Apollo-11/blob/master/Luminar...
- djmips 10 months ago
- jfoutz 10 months agoWhen the MacBook got the acceleration sensor, I hacked up a little program to estimate velocity, and a button to reset at stoplights. Some friends drove me around, it worked poorly. it did pretty ok on the highway, but awful in the city.
I think if I kept messing with it, it'd get a lot better, but I sorta lost interest. This was more of a fun weekend toy.
I think all phones have them, and they might be reachable through chrome/safari. And it is kinda fun to play with, but you'll probably hit sampling rate errors pretty quick. you gotta guess the shape of the curve between datapoints.
- benjam47 10 months agoIt is how Apollo navigated, although both the ground (via ground tracking) as well as the crew (via locating stars through a extant, and the Apollo computer having a database of the position of several dozen bright stars) could update their current position throughout the flight.
- embedded_hiker 10 months agoApollo used star sightings to check the accuracy of the gyros that measured which way the spacecraft was pointed. The stars could not be used to determine position like a ship at sea could do.
Besides inertial navigation, they had a transponder that would echo back a continuous pseudorandom bit stream, and the delay gave a precise measurement of distance.
- benjam47 10 months agoThank you for the correction, but are you sure that is accurate? I was definitely under the impression that although their position was normally updated by the ground (to the AGC, via their uplink capability), and the sextant was normally used to determine their orientation, the astronauts could use their optical equipment and calculations to determine their position as well as their orientation, albeit it with less precision. This NASA website (https://www.nasa.gov/history/afj/compessay.html#:~:text=Opti...) seems to say as much:
"Optical navigation subsystem sightings of celestial bodies and landmarks on the Moon and Earth are used by the computer subsystem to determine the spacecraft's position and velocity and to establish proper alignment of the stable platform."
And Wikipedia (https://en.m.wikipedia.org/wiki/Apollo_PGNCS):
"The CM optical unit had a precision sextant (SXT) fixed to the IMU frame that could measure angles between stars and Earth or Moon landmarks or the horizon. It had two lines of sight, 28× magnification and a 1.8° field of view. The optical unit also included a low-magnification wide field of view (60°) scanning telescope (SCT) for star sightings. The optical unit could be used to determine CM position and orientation in space."
- benjam47 10 months ago
- bigiain 10 months agoThe errors would be less of a problem than Apollo's, when your longest possible flight is only 45 minutes or so. And I'm not sure, but I guess the ballistic portion of the flight is uncontrolled (since the steering is from the rocket motors), so perhaps only the first few minutes are all it needs to maintain accuracy for?
- embedded_hiker 10 months ago
- dingaling 10 months agoThe little errors do compound, but the errors have been made progressively littler; a modern ring-laser gyro INS has a drift of one millidegree per hour or less.
Or you can add an external correcting factor, such the Trident's astronav system that takes star-shots to recalibrate the INS.
- beerandt 10 months agoI said it downthread, but GPS is even more absurd. And we take it for granted.
But it's based on the same idea, only getting position as a derivative of velocity. (And some borderline-magic statistics applied.)
And that's before taking into account the absurdity of how low power the broadcast signal is.
- CamperBob2 10 months agoGPS doesn't work that way. It uses instantaneous time-of-flight computation.
- beerandt 10 months agoHow do you think the 'instantaneous time-of-flight' computation is done?
There's a lot of math that phrase is hiding. It's not a magic black box. It just often seems that way.
- beerandt 10 months ago
- CamperBob2 10 months ago
- jonathanyc 10 months agoI also could not believe inertial navigation systems worked as well as they do when I first learned about them. At some point in time the most sophisticated IMUs were actually export-controlled!
Maybe this has changed or is ineffective now that smartphone/quadcopter IMUs have caught up.
- jandrewrogers 10 months agoAdvanced IMUs are still export controlled and the state-of-the-art is classified. The US military considers this a cornerstone technology and has invested heavily in R&D over the years. The IMUs that are widely available commercially have improved significantly over the years but so have the military versions.
- krisoft 10 months ago> Maybe this has changed or is ineffective now that smartphone/quadcopter IMUs have caught up.
They did not caught up. There are two kind of IMUs: one where you have to account for the rotation of the Earth during signal processing and one where there is no point because it will be lost in the noise anyway. The smartphone/quadcoptee IMUs are the second kind. The first kind is still export controlled.
- rcxdude 10 months agoconsumer-grade IMUs are still well below the performance of even much older military-grade IMUs (which tend to be impressive feats of precision engineering with pricetags to match, but also physically much larger). You'll still find anything that's useful for working out position over any time period is export-controlled (dual-use or stricter).
- jonathanyc 10 months agoThat's super interesting to learn, thanks for letting me know! I'm a software guy but I love learning about sensors, it's always amazing.
- jonathanyc 10 months ago
- jandrewrogers 10 months ago
- ghaff 10 months agoAt least modern ICBMs do a star sight to calibrate at the top of their trajectory but, yes, that’s what inertial guidance is. Draper Labs basically pioneered.
- rjsw 10 months agoOperation Black Buck [1] used inertial navigation.
- JR1427 10 months ago
- Zircom 10 months agoI mean it's a nuclear missile, millimeter accuracy isn't really necessary. Somewhere in the general vicinity is good enough for it's purpose of going boom.
- kens 10 months agoWell, accuracy makes a big difference if you're trying to hit a hardened target like a missile silo. Missile guidance has been a constant effort to squeeze out more and more accuracy. Minuteman I started with an accuracy of 2 km, but now Minuteman III is said to have an accuracy of 120 meters. The Peacekeeper (MX) missile, no longer in service, is said to have an accuracy of 40 meters. You can use a much, much smaller warhead if you're 40 meters away compared to 2 kilometers.
- chickenbig 10 months agoThe following was an interesting read on the super-fuze.
https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
- wkat4242 10 months agoOne thing I never understood is why they phased out the peacemaker and not the much older minuteman.
- chickenbig 10 months ago
- nox101 10 months agoshooting something 12000 miles away, 0.1% off is 12 miles. That's missing the target and will not destroy whatever you were trying to destroy
- lazide 10 months agoIn the early days, that’s why nukes went into the megaton range. Because then 12 miles will still destroy your target.
Then they got a lot more accurate than .1%
- lazide 10 months ago
- mannyv 10 months agoIn general, the USSR had bigger bombs because they weren't as accurate as US bombs. So yes.
- 10 months ago
- kens 10 months ago
- KK7NIL 10 months ago> surely all the little errors compound?
Random errors (i.e. noise) cancel out in the long run thanks to integration. You're then only left with systematic offset errors which can presumably be calibrated out to a large extent.
- petermcneeley 10 months agoReally depends on what you mean by random. If it is truly random then you will end up with a random walk.
- KK7NIL 10 months agoWe can assume the error will have a random (whether it's actually truly random or merely pseudo-random doesn't matter here, just assume it's indistinguishable from truly random for this discussion) and a non-random component.
The random component I assume to be gaussian (thermal noise, for example) and therefore symmetrical around the real value. It's obvious we can remove this type of noise through averaging (of which the core operation is integration).
The non-random component I assume to be a skew that can be calibrated out.
With these two assumptions in mind you can see that yes, it's indeed a random walk, but a very well behaved one.
- KK7NIL 10 months ago
- petermcneeley 10 months ago
- kevin_thibedeau 10 months ago
- firesteelrain 10 months agoYour article on the guidance system reminds me of this https://youtu.be/bZe5J8SVCYQ?si=LuVwiZ7NEI21czoH
- minkles 10 months agoHa that's great. I was expecting this for some reason https://www.youtube.com/watch?v=yXFh54fc8GM
- kens 10 months agoI refrained from including that link :-)
- beerandt 10 months agoEven as someone who's actually done the math that video is trying to explain(in an actual class covering missile geodesy), it's still so absurd.
But honestly only about half as crazy as GPS would sound if you tried to put it in similar terms. And that's before considering the signal itself is way below the noise floor.
As much as I love these technical writeups, I wish more people who understand the slightly expanded bigger picture/ implications of the missile technologies would write what they know before the generation goes extinct.
There's so many dots that are easily connected from articles like these... but I suspect some level of classification prevents those in the know from being able to publish.
The bulletin of atomic scientists is the only non-fringe source that ever comes close. (Their article on the new generation of warhead fuses is a great resource for those wanting to go down the rabbit hole. Even it now seems to have been scrubbed from their site. [0])
[0] https://web.archive.org/web/20170307194641/https://thebullet...
Eta working bulletin link: [1]https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
- mananaysiempre 10 months agoLooks like thyey just didn’t care enough to do a redirect: https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
- mananaysiempre 10 months ago
- beerandt 10 months ago
- minkles 10 months ago
- N_A_T_E 10 months agoWow, so this thing needs to be pointed directly at the target 8,000 miles away and will miss the target by the amount of error in aim.
"To target a Minuteman I missile, the missile had to be physically rotated in the silo to be aligned with the target, an angle called the launch azimuth. This angle had to be extremely precise, since even a tiny angle error will be greatly magnified over the missile's journey. " ... "The guidance platform was completely redesigned for Minuteman II and III, eliminating the time-consuming alignment that Minuteman I required. The new platform had an alignment block with rotating mirrors. Instead of rotating the missile, the autocollimator remained fixed in the East position and the mirror (and thus the stable platform) was rotated to the desired launch azimuth. "
- kens 10 months agoThere are two factors. First, any missile with inertial guidance needs to have a precise angle reference as a basis for the guidance system. If the guidance system starts off slightly wrong about which way is North, it's going to miss the target. Second, the guidance system in Minuteman I could only turn about 10 degrees from its initial angle before the wires would get tangled up. The solution in Minuteman I was to use the launch azimuth as the reference angle, so it was precisely lined up against this angle. Most of the alignment was physically rotating the missile, but the last bit of alignment was by constantly rotating the stable platform for alignment with the light beam from the autocollimator.
- ianbicking 10 months agoI noticed that too. That seemed odd at first read... after all, it has a guidance system, it's not relying on exact aim. I'm assuming it's more that its guidance system can only has so much fuel at its disposal and ability to correct errors, and if it's aimed incorrectly it would exhaust its fuel before it corrects its trajectory.
- ethbr1 10 months agoSometimes it's less work to engineer a hard problem into an easy one, than to solve the hard problem.
Most of the tech for the Minuteman I was developed in the mid-1950s.
With that level of processing, would you rather solve a 2d problem by precisely orienting the missile before launch? Or a 3d one by requiring it to orient during flight?
Keep in mind: any equipment to self-orient in-flight also needs to be carried on the missile itself, while being tolerant of launch, acceleration, and reentry forces.
Any precision machinery at the launch site has no such requirements.
- aeonik 10 months agoThis doesn't make sense to me. I would assume the engines starting by themselves would introduce enough error to throw the entire system off. Let alone natural seismic events in the ground, plus wind.
I would guess you must solve the 3D problem at least to some degree.
- aeonik 10 months ago
- ethbr1 10 months ago
- ecshafer 10 months agoShooting a projectile, accounting for the earths rotation and wind, is essentially a solved problem (with computers). So I don't think this is that outlandish and I imagine it gets pretty accurate. Creating an analytical solution by hand is a junior level physics problem.
- kens 10 months ago
- minkles 10 months agoJust a bit of additional trivia. Jim Williams (somewhat famous EE at Linear) had a minuteman computer on his living room wall known as "the tapestry": https://www.eetimes.com/photo-gallery-remembering-jim-willia... (last picture in particle). Not sure what revision.
- kens 10 months agoAuthor here if anyone has questions...
- ulnarkressty 10 months agoThe article states that the system was cooled using a solution of sodium chromate to inhibit corrosion. However the wiki page of sodium chromate states that it is very corrosive. Is it a typo or something?
It's also mentioned that the computer uses one of the first integrated circuits for miniaturization. Do you know if this can be definitely traced to advances in industrial/consumer products? It's a common trope that military research trickles down - so it's a "good" thing. It's not clear if this actually happens or if progress would have been made eventually without the need for these machines.
- kens 10 months agoSodium chromate is highly corrosive to humans (as well as carcinogenic, see the movie Erin Brockovich). However, it inhibits corrosion in metal, acting as a passivating inhibitor, forming some sort of protective oxide.
I've been doing a lot of research on the impact of Minuteman and Apollo on the IC industry (which led to the current post). The Air Force likes to take credit for the IC industry, as does NASA, but the actual influence is debatable. My take is that both projects had a large impact on the IC industry, more from Minuteman. However, even in the absence of both projects, there was a lot of interest and demand for ICs. If I had to take a quantitative guess, I'd say that those projects advanced ICs by maybe a year, but the basic trajectory would have remained the same.
- dboreham 10 months agoKen, the story I heard wasn't so much that the MM3 demand created the IC industry, but rather that it created the quality culture that then led to ICs being widely accepted, because they were reliable. The AF had such purchasing power due to the program that they were able to impose quality standards on the industry that hitherto were not expected.
- dboreham 10 months ago
- philipkglass 10 months agoThe article states that the system was cooled using a solution of sodium chromate to inhibit corrosion. However the wiki page of sodium chromate states that it is very corrosive. Is it a typo or something?
Chromates are effective corrosion inhibitors for aluminum alloys and some other metals. Here's a brief article about how they work with aluminum:
"Inhibition of Aluminum Alloy Corrosion by Chromates"
https://www.electrochem.org/dl/interface/wtr/wtr01/IF12-01-P...
When the Wikipedia entry's "Safety" section says that sodium chromate is corrosive, in context it means "destructive to human tissue by contact." That is, like sodium hydroxide (lye) and many other chemicals, in concentrated form it can destroy skin and eyes.
- kens 10 months ago
- bloopernova 10 months agoDo you have any plans to write about World War 2 era mechanical firing computers? I searched your blog but didn't see anything.
Or maybe early RADAR systems of 1942 and later?
(been reading about WW2 Pacific naval/air wars, and I am curious about these new-at-the-time technologies)
- kens 10 months agoI planned to write about the electromechanical Torpedo Data Computer used in WWII, but I got distracted.
- kens 10 months ago
- OldSchool 10 months agoExcellent presentation, thank you!
The machinery is ironically beautiful to look at!
How did this compare to its approximate contemporary in the USSR ?
- 10 months ago
- jojobas 10 months agoSoviet 70's machines were hand-woven ferrite plate, stacked PCB sandwiches. Not pretty at all.
- 10 months ago
- izacus 10 months agoHow does a 1-bit serial computer actually work? E.g. how does an ADD operation look like? It's a bit hard to picture.
- kens 10 months agoIn a serial computer, you have a 1-bit ALU, say an full adder that generate a sum and carry. Each clock cycle you read two bits and feed them into the adder, and then you write back the sum. You hold the carry in a flip-flop to use in the next clock cycle. It's just like doing a binary addition with pencil and paper, one bit at a time.
Note that you need to start with the lowest bit with a serial computer, which explains why x86 is little-endian. It goes back to the Datapoint 2200, a desktop computer made from TTL chips and running serially. The Intel 8008 processor was a copy of the Datapoint 2200 (as was the Texas Instruments TMX 1795). Although the 8008 was parallel, it copied the little-endian architecture of the Datapoint 2200.
- seoulbigchris 10 months agoI've often wondered if serial computers could have a useful role again. At very high clock speeds and wide data paths, you hear about trouble controlling signal skews. In contrast, imagine a serial computer clocking data around at 8 GHz vs. an 8-bit computer clocking data at 1 GHz. You have to deal with faster speeds, but no skew, and it seems like a 1-bit ALU might be simpler (and faster) than a 64-bit one.
- izacus 10 months agoHmm, I see - how do the opcodes work and jumping then? Do you also read them bit-by-bit and reconfigure the ALU / codepaths? Is addressing also single-bit?
- seoulbigchris 10 months ago
- kragen 10 months agoif you write down two binary numbers on paper and add them, you will almost certainly do the computation bit-serially, adding each pair of corresponding bits with the carry from the previous operation. serial computers work the same way
- kens 10 months ago
- metadat 10 months agoWhat is the purpose of the window?
(As labeled in https://static.righto.com/images/minuteman-mmiii/guidance-la...)
- QuinnyPig 10 months agoFrom the article:
> Also note the window in the side of the missile to allow the light beam from the autocollimator to reflect off the guidance platform for alignment.
- metadat 10 months agoThanks, I finished reading the article while in the air and realized my faux pas without any Internet! Cheers.
It's labeled in another image towards the end:
- metadat 10 months ago
- QuinnyPig 10 months ago
- nullhole 10 months agoAny opinion on the book 'Inventing Accuracy'? It covers the Minuteman guidance system for a few chapters.
- kens 10 months agoI've got the book on my desk right now :-) It's a bit of an unusual book because it is full of technical details but it also has a fair bit of sociological content like "the construction of technical facts", "technological determinism", and "sociology of technological knowledge". This is in contrast to, say, "Minuteman: A Technical History", which is strictly facts and details. They are both good books, but it is interesting how they have completely different styles and focuses.
- nullhole 10 months agoI agree with your observations about "Inventing Accuracy". Personally I found the sociology focus a bit unexpected, and maybe a little too strong in some chapters, but still a worthwhile point of view.
I will definitely be taking a look at "Minuteman: A Technical History". Books dealing at least in part with the history of IMUs are few and far between.
- nullhole 10 months ago
- kens 10 months ago
- ulnarkressty 10 months ago
- jonathanyc 10 months ago> The new guidance platform also added a gyrocompass under the alignment block, a special compass that could precisely align itself to North by precessing against the Earth's rotation. At first, the gyrocompass was used as a backup check against the autocollimator, but eventually the gyrocompass became the primary alignment. For calibration, the alignment block also includes electrolytic bubble levels to position the stable platform in known orientations with respect to local gravity.
Had never heard of gyrocompasses before. I worked on a small robot in the past and remember having to calibrate the magnetic compass, which was not very accurate (similar to smartphone compasses). I never thought about how they’d get super precise headings for ICBMs.
The Encyclopedia Britannica article on gyrocompasses is really good. Here it explains why you can’t use a gyrocompass on a vehicle on fast aircraft (and I guess small robots that are jostled around a lot):
> A major contribution by Schuler was the discovery that, when the period of oscillation is 2π√(Earth radius/gravity), the heading precession of the gyroscope spin-axis due to acceleration is exactly the rate of change of the angle between the apparent and true meridians seen on a moving vehicle. The gyrocompass will then read true north at all times if its indicating reference is offset by the angle between these two meridians. The angle, at ship speeds, is a direct function of the north-south speed and is easily set into the system. The need for accurate speed measurement for this offset is the main reason why a gyrocompass is not practical for use in aircraft.
https://www.britannica.com/technology/gyrocompass
Love this article!
- blantonl 10 months agoThese systems are so vastly complicated, old, and rarely if ever launched. These aren't like data center generators which have testing schedules etc, and STILL there are failure points.
I really wonder what the failure rate would be if they were all actually launched today. And I mean failure, from not lifting off, to failure in flight, to misguided warheads etc.
- krisoft 10 months agoBut they do have testing schedules. They certainly tests the electronics regularly. And every so often they randomly pick a missile and launch them from Vandenberg.
https://www.spaceforce.mil/News/Article-Display/Article/3796...
> I really wonder what the failure rate would be if they were all actually launched today
I hope we will never find out. But certainly there would be many duds. But this is calculated into the effectiveness of the system by simply having more missiles. That is how it achieves its goal of dettering a would be attacker. (Not even talking about how there are two other totaly separate legs of the nuclear triad with dissimilar personel and technical solutions.)
- m_mueller 10 months ago> randomly pick a missile and launch them from Vandenberg
Jeff! Did you remember to take out the warheads? Jeff?!
- kens 10 months agoThat reminds me of the 2007 incident when the Air Force meant to transfer twelve unarmed cruise missiles from North Dakota to Louisiana but loaded up six nuclear-tipped missiles by mistake. The missiles remained unprotected on a B-52 for 36 hours before someone noticed the missiles were nuclear. A whole lot of people including 8 generals got in trouble over this.
https://en.wikipedia.org/wiki/2007_United_States_Air_Force_n...
- mrguyorama 10 months agoSomewhat soberingly, earlier in the war with Ukraine, Russia managed to launch a ballistic missile with a concrete "Warhead simulator" installed, literally a mass designed to test the launch vehicle without using a nuclear device.
If that was an accident, that means they didn't properly know which warheads are where. That's.... upsetting.
- kens 10 months ago
- m_mueller 10 months ago
- justin66 10 months agoYou can watch video of the most recent test, a little more than a month ago, of a Minuteman III. This is a short clip:
https://www.youtube.com/watch?v=zUg7x1zo7D0
They can test the missiles and reentry vehicles, everything except the nuclear warhead. The closest those come to a test is a supercomputer simulation, since those tests are forbidden by treaty.
Minuteman III has an excellent but not perfect [0] failure rate. Some other older systems, like the UK's submarine launched Trident missiles... not so much.
[0] https://www.airandspaceforces.com/icbm-test-failure-nuclear-...
- arethuza 10 months agoTh UK Trident 2 missiles are literally the same missiles used by the US submarines operating in the Atlantic - both sets of submarines are supplied by a shared pool:
https://en.wikipedia.org/wiki/UGM-133_Trident_II
However, the warheads on the UK missiles are designed and manufactured by the UK.
- justin66 10 months agoInteresting. Are recent US missile tests at sea as bad as the recent UK tests? I don’t remember seeing news to that effect.
- justin66 10 months ago
- arethuza 10 months ago
- cpgxiii 10 months agoStrategic weapons are tested regularly, except for the warhead. The Trident II D5 has had about 200 tests in the last 35 years. That's about the same number of test missiles expended as are actively deployed at any given time. While there are a theoretical maximum of 344 deployed at any one time (14 Ohio-class, each with 20 tubes, plus 4 Vanguard-class with 16 tubes) some number of those boats are unarmed in refit at any given time.
- minkles 10 months agoThey have operational models with statistical failures included so they understand what the interception and failure probabilities likely are for each item at component level. You can design that into a system and test for it.
Obviously you can't factor in unknown problems but that's what drills and test flights are for.
- dboreham 10 months agoAir force takes one at random, transports it to Vandenberg sans warhead and lights the fuse to see if it works. Or at least they used to. I also heard that the Soviet equivalent of this random testing process was to simply retarget a random missile and launch it straight out the operational silo.
- krisoft 10 months ago
- Ringz 10 months agoImpressive work and very interesting! Since I was instantly interested in the tiny „window“ and its purpose I found a little error:
„Aligning the missile was a tedious process that used the North Star*t* to determine North.„
- kens 10 months agoThanks! I fixed that.
- kens 10 months ago
- bun_terminator 10 months agoI have a morbid curiosity to know how much of all that old tech would actually work in a full scale nuclear war, launching all missiles. Seems so well thought-out, but also incredibly hard to test. Really fascinating article!
- kens 10 months agoThey did dozens of tests of the Minuteman missiles and reentry vehicles. The warheads were tested underground until the comprehensive test ban treaty of 1996. So it's pretty likely that the systems would work if needed. One risk is that something may have gone wrong with the warheads over 30 years. (Of course they maintain them, but without testing you can't be sure.) Another risk is that you don't know how the missiles would function in an environment with nuclear blasts and EMP all over the place. They put a whole lot of effort into mitigating these factors, but you can't be sure. Hopefully we never find out.
- leeter 10 months agoNote: While none of the Annex 2 countries that are signatories have conducted tests since 1996; the treaty never took effect because it was never ratified by all the required countries. Most notably the US, China, and Russia (although all three signed). In 2023 Russia officially withdrew, allegedly based on the US non-ratification. At least one political candidate for the presidency in the US has advocated for resuming testing. It is not inconceivable that testing could resume in the near future.
Opinion: I don't think the US would if Russia or China didn't first. China likely won't for the same reason the US doesn't need to: they have super-computers and the sims line up with the data from prior tests. Russia might however if only to saber rattle, although they likely don't need to either. Russia however is likely not in any hurry to have a test failure right now. So while testing could resume, I wouldn't put money on it.
- leeter 10 months ago
- Joel_Mckay 10 months agoThere was an area of redundant symmetric electronic design, that auto compensated for component level failures. I remember reading an "aerospace" manual all about it when I was a kid. It was necessitated when the tolerance and reliability of components were terrible by today standards.
Note too, that mil spec silicon is different in that it is resistant to CMOS latch-up, redundant CRC protected self-correcting consensus register ops, and large gate sizes less sensitive to Gamma radiation.
It was an interesting time, and a few people still think living under the Sword of Damocles builds character. =3
- akira2501 10 months agoWhy would it be hard to test? We have our own anti-missile technology, so it's ostensibly as simple as not putting a payload on the missile, then launching it at your own test range.
- dumah 10 months agoThe physical environment these weapons were designed for is extreme and only possible to simulate piecemeal.
Each stage needs to function in the presence of nearby nuclear detonations, resulting from both adversary and friendly weapons.
These detonations are expected to cause severe shock, thermal, radiation, and electromagnetic transients.
In the case of the most important targets, it is guaranteed that numerous detonations near the target, from ABM systems and friendly impacts, will occur, and these systems have been engineered and are expected to perform reliably under such conditions.
- akira2501 10 months agoThis weapon is an ICBM. The payloads are delivered to orbit then launched at the target from there. You're already facing severe shock, thermal, radiation and EM transients just to get to orbit. Once there, you're ultimately dropping MIRVs, the design of which is considerably simpler.
The delivery vehicle and the reentry/payload vehicle have entirely different life cycles and deployment concerns.
- akira2501 10 months ago
- bun_terminator 10 months agoI was thinking mostly of the bits of the tech designed for working when the launch site is hits with nuclear explosions
- dumah 10 months ago
- kens 10 months ago
- aussieguy1234 10 months agoSo. The world could be blown up with just 8kb of memory. No need for a killer AI with hundreds of GB's of vram.
- somat 10 months agoThere is a well written video essay on the inner workings of the d-17 computer used on the minuteman 1
Minuteman D-17b: The Desktop Computer Was Born in an ICBM
https://www.youtube.com/watch?v=MJPnZzZtswc (Alexander the ok)
- mrguyorama 10 months agoThis is Youtuber has had several very well researched and thorough videos about topics that readers of Ken would enjoy, including Buran, the F-14 Air data computer, Elite, and the birth of Digital fly by wire out of the Apollo program.
Check him out and give him slack for his vocal fry. It's mildly annoying but the content is just so good.
- mrguyorama 10 months ago
- artemonster 10 months agoA testament to human ingenuity and genius, work of art even. The machined parts, the crude electronics, all of it
- IamTC 10 months agoI believe parts of the subsea industry uses a similar concept, i.e., gyroscope based for inertial navigation.
Obtaining position & veocity: I think it even more interesting when one compares the difficulties of getting these fundamental navigation data in an aerial, ground and undersea platforms.
- LarsDu88 10 months agoSo much discrete circuitry and now any bum can get the same performance from a 15 year arduino
- datavirtue 10 months agoPurely a deterrent. No one in their right mind would try to launch these expecting them to hit their target.
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- maxglute 10 months agoWhat's the actual color of the yellow paint? Goldish like first pic of lemonish like latter pics. Contrast/aesthetics of the gold is just chefs kiss. There's something about American MIC pallette that rarely miss.
- ornateelephant 10 months agoIt's the corrosion protective primer, usually containing zinc chromate. Colours may vary slightly but they are usually some shade of yellowy green.
https://aviation.stackexchange.com/questions/49961/why-are-a...
- ornateelephant 10 months ago
- ThinkBeat 10 months agoHow did you reprogram the destination on the missiles?
- kens 10 months agoIt depends. For Minuteman I, the missile needed to be physically rotated in the silo to be aligned with the target. Then the "Targeting Van" connected to the missile, downloaded the new targeting data to the disk, and checked that the guidance system was aligned. As for the targeting data, it was generated by a mainframe that determined the right trajectory and produced the optimized navigation polynomials that the targeting algorithm used. It was something like 740 words of data per target so only two targets could fit in the computer.
Minuteman III used a smarter targeting algorithm that only needed 70 words of data per target, so the missile could support something like 8 targets at once, selected by a knob on the launch console. (The launch officers didn't know what the targets were; they were just told to use target #3 for example.) The targeting data was read off punched tape for Minuteman II and a magnetic tape cartridge for Minuteman III.
- beerandt 10 months agoIt was organized primarily via wargame scenarios, such that one target group comprised targets for a given scenario.
Simplified launch orders via the football, etc.
One group scenario might have been silo coordinates for an offensive first-strike. One group city coordinates for launch on warning strategic counter-strike, etc.
Each missile got a target from each scenario list programmed into a 'memory slot' with some overlap.
The organization/ optimization is mind-boggling.
But few understand that this is WHY the wargames and strikes had to be pre-planned ahead of time. It wasn't political hubris, but a technical requirement due to memory allocation.
- krisoft 10 months ago> It wasn't political hubris, but a technical requirement due to memory allocation.
I don’t understand why it would be “political hubris”.
Proper targeting is hard work. You need to map your enemy territory to make optimal choices. Not just in a geographical “what are the coordinates” sense, but also in a “what are the important nodes to get the coordinates for” sense. At the same time your enemy doesn’t want to be mapped and resists your efforts.
Doing this properly takes time. On the order of months. But once you are under attack you don’t have that time. So you have to select your targets ahead of time.
It is not because the missiles have limited memory. If they would have needed more memory they would have added more memory. It is because the President doesn’t have time once under attack to name each enemy railway depot one by one and decide which ones are important, and which ones are better left unharmed. Instead what they have is a menu of options. Something like option 1 destroy all red military ports, military airports and military bases; option 2 destroy major military installations plus main industrial centers; option 3 destroy main population centers.
Thinking that the memory allocation is why it is the way it is is super tech centered and quite frankly putting the cart before the horse.
- krisoft 10 months ago
- beerandt 10 months ago
- kens 10 months ago
- ThinkBeat 10 months agoA cheerful thought is that according to atomic scientists the world is closer to nuclear holocaust now, than we have ever been.
The future so bright, I gotta wear shades.
- ThinkBeat 10 months agoOne of the great things about chemical propulsion rockets is that they can take off with little to no prep at all. Ready to go at the press of a button.
The scary thing is that, when left alone for a long time, and these rockets have been, "the plates" keeping the chemicals from meeting each other ahead of schedule, corrodes, just a tiny bit at a time. each time raising the possibility of premature ejaculation just a tiny little fraction.
- kens 10 months agoI think you're talking about the Titan missiles, which use hypergolic propellants. The Minuteman missiles are solid fuel, so there are no separated chemicals.
- beerandt 10 months agoThere are separated chemicals, the hypergolic means no ignition source required.
Which to his point would be even more scary, but just isn't the actual real world risk with the way the things were designed.
Plus hypergolics are usually toxic on their own, even without mixing and/or booming, in a quieter, more-deadly-to-technicians way.
Spills and defueling and meeting well-intentioned but bad safety guidelines that require abundant fiddling were the real source of danger. More fiddling == bad.
Iirc, the fuels/oxidizers/reagents/ whatever-liquids mainly behaved like aluminum oxidizing, such that reaction with the tanks components actually created an increased buffer layer of oxidation/ protection.
Tank corrosion wasn't high on the list of risks after it was figured out on a per-chemical basis.
I think it's one of the aspects covered fairly well in (the great, often posted) Ignition! [0]
- krisoft 10 months agoThere is a bit of a misunderstanding here.
The minuteman missiles are solid fueled. There are no liquids and no hypergolics involved in the stages which loft it towards the enemy. Structurally it is more similar to a candle than a fuel tank. There are no spills or defueling with this system. This is a fact. In this system you won’t find a separate oxidiser/fuel. The two components are mixed together and they form a kind of rubber like cylinder with a hole in the middle. The hole is shaped appropriately so the rocket engine burns at the right rates.
There are hypergolic fuels at the very end of the rocket in the payload. They are used for deorbiting and to control the return vehicles. But it is a much smaller part of the whole missile. (Both by mass, and by encapsulated energy.)
- krisoft 10 months ago
- beerandt 10 months ago
- kens 10 months ago
- spoonfeeder006 10 months agoInteresting tech and all, but ultimately efforts like this are a waste. If we humans could instead get over our self-perceived need to engage in warfare for childish reasons then we could dedicate such efforts to more productive things like helping homeless people get housing and skills, or developing better psychological sciences to help drug addicts get free from their disease of addiction, you name it
> O SON OF SPIRIT! The best beloved of all things in My sight is Justice; turn not away therefrom if thou desirest Me, and neglect it not that I may confide in thee. By its aid thou shalt see with thine own eyes and not through the eyes of others, and shalt know of thine own knowledge and not through the knowledge of thy neighbor. Ponder this in thy heart; how it behooveth thee to be. Verily justice is My gift to thee and the sign of My loving-kindness. Set it then before thine eyes. > > ~ Baha'i Teaching
- CamperBob2 10 months agoIt would be great if we could all share that sentiment. But ask the Ukrainians how unilateral disarmament worked out for them. Unfortunately, it seems that this particular waste of resources and intellect is still necessary.
- spoonfeeder006 10 months ago> O rulers of the earth! Be reconciled among yourselves, that ye may need no more armaments save in a measure to safeguard your territories and dominions. Beware lest ye disregard the counsel of the All-Knowing, the Faithful.
> Be united, O kings of the earth, for thereby will the tempest of discord be stilled amongst you, and your peoples find rest, if ye be of them that comprehend. Should any one among you take up arms against another, rise ye all against him, for this is naught but manifest justice.
> (“Gleanings from the Writings of Bahá’u’lláh”, pp. 253-254)
- spoonfeeder006 10 months agoSorry, I don't mean anything against legitimate self defense, I'm talking rather about "self-perceived need to engage in warfare for childish reasons"
Examples of that would include ego, greed, petty revenge, etc...
But I guess the way I said it did come across that way, so yeah, my bad
I'm just saying that if we could evolve past such petty ego-based sentiments in the world, then wouldn't such pressure to develop weaponry in such massive amounts, and hence we could focus on actually making a functioning society
- shiroiushi 10 months ago>I'm just saying that if we could evolve past such petty ego-based sentiments in the world
That would be nice, but it seems that would make people no longer human. Happily following a petty ego-based Dear Leader's orders into warfare seems to be the norm for much of the human population, looking at history, so this tendency appears to be deeply-rooted into the human psyche.
- shiroiushi 10 months ago
- spoonfeeder006 10 months ago
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- CamperBob2 10 months ago
