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My father worked on the guidance system for the Trident nuclear missile at Singer-Kearfott for many years and this is mostly accurate. There was a lot of geomet

My father worked on the guidance system for the Trident nuclear missile at Singer-Kearfott for many years and this is mostly accurate. There was a lot of geometry involved. They used to test launch the missiles back during the cold war from submarines off of California. The missile would cross the continental US and land in the water off Florida. The Soviets would invariably send "fishing" boats to measure the tests but the coast guard would never shoo them away -- they wanted the Soviets to know just how accurate these missiles were. And they were accurate. It blows my mind what was possible with analog tech.

ChatGTP 3y ago
I find it highly inspiring. I love analog tech, simple but generally insanely robust when done right.
jacquesm 3y ago
It's not just analog tech: it's actual engineering. The hardware we have is amazing, most of our software royally sucks. But software done right is also most impressive.
- canadianfella 3y ago
  [dead]
- PNewling 3y ago
  To be fair, you can do a lot when you throw a near endless supply of money at things. Definitely impressive though.
  - titzer 3y ago
    To get great software, you need a small team and give them extremely clear requirements of what it should do with an assload of extremely clear testcases.
    - sasaf5 3y ago
      And lots of time to tune things and solve all little problems, and manually implement things when abstractions hamper performance.
    - fsloth 3y ago
      This is a fairly generalizable rule in any engineering, unless you really are running the Apollo program (then when divide-and-conquering should probably remember this rule).
    - hoseja 3y ago
      This is running into the no-code problem of clear-enough requirements being as complex as the code, via Kolmogorov.
    - taneq 3y ago
      The best software comes from a small team of top level devs who are also top level subject matter experts on the software’s domain. This doesn’t happen very often.
    - robbs 3y ago
      It doesn't have to be a small team. See "They Write The Right Stuff".
      - 2rsf 3y ago
        And even they make mistakes, software contains much more moving parts than hardware. https://space.stackexchange.com/questions/37110/what-was-the-nature-of-the-known-bugs-in-the-space-shuttle-software https://space.stackexchange.com/questions/37110/what-was-the...
        tekla 3y ago
        Wow, thats a hell of a HN thing to say.
        iudqnolq 3y ago
        > Use of pointers required a written, approved, variance from the SW standards board. All the code was formally peer reviewed by at least 6 people. More complicated code would be reviewed by 20+ people - in the same room.
- drt5b7j 3y ago
  Do you think the "software engineering" people are giving engineering a bad name? "Christian scientists" are Christians who attach themselves to the word science because science has such a powerful reputation. In their case I'm not worried about their trickery because everyone recognizes this. Everyone knows that Christian scientists are not scientists. With software engineering it's not as clear. It's possible to create software applying engineering principles, but that's not what 99%+ of what is called "software engineering" is. And because most people don't recognize this, I think eventually this might run off "engineering".
  - adolph 3y ago
    In case you are wondering about all those “reading rooms” you may see in various cities: Not to be confused with Christianity and science, Christians in Science, Christians in science and technology, or Scientology. Christian Science is a set of beliefs and practices which are associated with members of the Church of Christ, Scientist. Adherents are commonly known as Christian Scientists or students of Christian Science, and the church is sometimes informally known as the Christian Science church. It was founded in 19th-century New England by Mary Baker Eddy, . . . https://en.wikipedia.org/wiki/Christian_Science https://en.wikipedia.org/wiki/Christian_Science
  - tester756 3y ago
    Software is engineering.
    - mrguyorama 3y ago
      The near entire majority of software development in the modern world is digital plumbing. Very very few organizations practice software engineering
      - tester756 3y ago
        What's ur definition of "engineering" then
avs733 3y ago
As far as I’m aware test shots of both us Air Force and navy icbms off the west coast went to Kwajalein atoll. Some other interesting details… Naval icbms have star tracking for alignment and correction but land based ones do not. The reasoning is that they are all dead reckoning…which requires knowing the initial location. The silo doesn’t move, but the subs do. Their location is tracked with another inertial guidance system but that adds error, so they use the star tracking. Overall, the inertial navigation systems in modern icbms are not the limited in accuracy. My favorite…there was a lot of pushback inside the us military on investing in increasing the accuracy of naval ICBMs. Doing so was seen as communicating/implying a shift in strategic goal from targeting cities (lower required accuracy) to targeting hardened facilities (higher required accuracy). That was seen as confrontational because sun based nuclear weapons had been generally treated as a second strike capability, but the primary reason to have the ability to target hardened facilities was for a first strike
- ceilingcat0 3y ago
  From what I recall land missiles (minuteman) does its own alignment while in the silo to give it what it needs to hit that window in space where the RV detaches. There some documentation and YouTube videos depicting the alignment process.
  - avs733 3y ago
    Yup. But that’s based on knowing where the silo is, they are less mobile than subs (or trucks or trains). The alignment is all based on dead reckoning from where it started to where it’s going to know where it is, where it wants to be, and how to steer there.
- kijiki 3y ago
  > there was a lot of pushback inside the us military on investing in increasing the accuracy of naval ICBMs. The book "Inventing Accuracy" covers this in detail. Fascinating historical perspective. https://mitpress.mit.edu/9780262631471/inventing-accuracy/ https://mitpress.mit.edu/9780262631471/inventing-accuracy/
Full_Clark 3y ago
The guidance systems had to account for local variations in gravity as the missile flew to its target. One of the reasons ballistic missile accuracy improved so much was that measurements and mapping of these local anomalies improved so much. Most are due to magma reservoirs or large mineral deposits. Some are well-known in their effect, but their specific cause is still unknown: https://eos.org/science-updates/seismologists-search-for-the-indian-oceans-missing-mass https://eos.org/science-updates/seismologists-search-for-the...
- 2rsf 3y ago
  That's for Inertial Navigation Systems, they measure acceleration and from that integrate your position.
avs733 3y ago
Other funny note…for all the Silicon Valley folk on HN…the trident missles the US uses on submarines are built in Sunnyvale. I’m imaging most on here have read some/all of the secret history of Silicon Valley posts, but if you haven’t they are great

ChatGTP 3y ago

I find it highly inspiring. I love analog tech, simple but generally insanely robust when done right.

jacquesm 3y ago

It's not just analog tech: it's actual engineering. The hardware we have is amazing, most of our software royally sucks. But software done right is also most impressive.

canadianfella 3y ago
[dead]
PNewling 3y ago
To be fair, you can do a lot when you throw a near endless supply of money at things. Definitely impressive though.
- titzer 3y ago
  To get great software, you need a small team and give them extremely clear requirements of what it should do with an assload of extremely clear testcases.
  - sasaf5 3y ago
    And lots of time to tune things and solve all little problems, and manually implement things when abstractions hamper performance.
  - fsloth 3y ago
    This is a fairly generalizable rule in any engineering, unless you really are running the Apollo program (then when divide-and-conquering should probably remember this rule).
  - hoseja 3y ago
    This is running into the no-code problem of clear-enough requirements being as complex as the code, via Kolmogorov.
  - taneq 3y ago
    The best software comes from a small team of top level devs who are also top level subject matter experts on the software’s domain. This doesn’t happen very often.
  - robbs 3y ago
    It doesn't have to be a small team. See "They Write The Right Stuff".
    - 2rsf 3y ago
      And even they make mistakes, software contains much more moving parts than hardware. https://space.stackexchange.com/questions/37110/what-was-the-nature-of-the-known-bugs-in-the-space-shuttle-software https://space.stackexchange.com/questions/37110/what-was-the...
      - tekla 3y ago
        Wow, thats a hell of a HN thing to say.
      - iudqnolq 3y ago
        > Use of pointers required a written, approved, variance from the SW standards board. All the code was formally peer reviewed by at least 6 people. More complicated code would be reviewed by 20+ people - in the same room.
drt5b7j 3y ago
Do you think the "software engineering" people are giving engineering a bad name? "Christian scientists" are Christians who attach themselves to the word science because science has such a powerful reputation. In their case I'm not worried about their trickery because everyone recognizes this. Everyone knows that Christian scientists are not scientists. With software engineering it's not as clear. It's possible to create software applying engineering principles, but that's not what 99%+ of what is called "software engineering" is. And because most people don't recognize this, I think eventually this might run off "engineering".
- adolph 3y ago
  In case you are wondering about all those “reading rooms” you may see in various cities: Not to be confused with Christianity and science, Christians in Science, Christians in science and technology, or Scientology. Christian Science is a set of beliefs and practices which are associated with members of the Church of Christ, Scientist. Adherents are commonly known as Christian Scientists or students of Christian Science, and the church is sometimes informally known as the Christian Science church. It was founded in 19th-century New England by Mary Baker Eddy, . . . https://en.wikipedia.org/wiki/Christian_Science https://en.wikipedia.org/wiki/Christian_Science
- tester756 3y ago
  Software is engineering.
  - mrguyorama 3y ago
    The near entire majority of software development in the modern world is digital plumbing. Very very few organizations practice software engineering
    - tester756 3y ago
      What's ur definition of "engineering" then

avs733 3y ago

As far as I’m aware test shots of both us Air Force and navy icbms off the west coast went to Kwajalein atoll. Some other interesting details… Naval icbms have star tracking for alignment and correction but land based ones do not. The reasoning is that they are all dead reckoning…which requires knowing the initial location. The silo doesn’t move, but the subs do. Their location is tracked with another inertial guidance system but that adds error, so they use the star tracking. Overall, the inertial navigation systems in modern icbms are not the limited in accuracy. My favorite…there was a lot of pushback inside the us military on investing in increasing the accuracy of naval ICBMs. Doing so was seen as communicating/implying a shift in strategic goal from targeting cities (lower required accuracy) to targeting hardened facilities (higher required accuracy). That was seen as confrontational because sun based nuclear weapons had been generally treated as a second strike capability, but the primary reason to have the ability to target hardened facilities was for a first strike

ceilingcat0 3y ago
From what I recall land missiles (minuteman) does its own alignment while in the silo to give it what it needs to hit that window in space where the RV detaches. There some documentation and YouTube videos depicting the alignment process.
- avs733 3y ago
  Yup. But that’s based on knowing where the silo is, they are less mobile than subs (or trucks or trains). The alignment is all based on dead reckoning from where it started to where it’s going to know where it is, where it wants to be, and how to steer there.
kijiki 3y ago
> there was a lot of pushback inside the us military on investing in increasing the accuracy of naval ICBMs. The book "Inventing Accuracy" covers this in detail. Fascinating historical perspective. https://mitpress.mit.edu/9780262631471/inventing-accuracy/ https://mitpress.mit.edu/9780262631471/inventing-accuracy/

Full_Clark 3y ago

The guidance systems had to account for local variations in gravity as the missile flew to its target. One of the reasons ballistic missile accuracy improved so much was that measurements and mapping of these local anomalies improved so much. Most are due to magma reservoirs or large mineral deposits. Some are well-known in their effect, but their specific cause is still unknown: https://eos.org/science-updates/seismologists-search-for-the-indian-oceans-missing-mass https://eos.org/science-updates/seismologists-search-for-the...

2rsf 3y ago
That's for Inertial Navigation Systems, they measure acceleration and from that integrate your position.

avs733 3y ago

Other funny note…for all the Silicon Valley folk on HN…the trident missles the US uses on submarines are built in Sunnyvale. I’m imaging most on here have read some/all of the secret history of Silicon Valley posts, but if you haven’t they are great