221–230 of 358 posts
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To be fair, you can do a lot when you throw a near endless supply of money at things. Definitely impressive though.
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.
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My guess would be for physical calibration of the INS gyroscope rotors? https://navsource.org/archives/08/PolarisHistoryGEX1.htm (see bottom / appendix for examples of Polaris-era INS) Given the CEP they were aiming for, and amount of time they had to fiddle with them, I'd guess they started very carefully with the physical precision of components.
CEP: Circular error of probable or probability. The radius of a circle within which 50% of rounds will be found. For the V-2 rocket this was 4.5 km. For the Minuteman III missile, 240m. Blast effects decrease with the cube of the radius, so a more accurate weapon means a smaller effective warhead. The "Flying Ginsu" AGM-114 Hellfire missile has a CEP of 5 meters or less, and uses blades rather than explosives to mini…
But then withdrawn from service due to treaty, because with that accuracy, first striking your target's silos and hardened facilities starts to be a viable option.
Sometimes you can be too accurate.
Also, related, the W76-1/Mk4A height-adjusting fuze solved this this in a different way, by recognizing that there's a 3D kill-volume (above and around the target) rather than a 2D kill circle.
Consequently, if you aim beyond the target and have your warhead measure actual height vs expected once on a ballistic trajectory, you can adjust the fuzing height to detonate within the volume, even if you overshot the target. See figures 2 and 3. https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
Un/fortunately, this puts us back into viable first-strike territory.
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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 guidan…
I'm recounting second hand so can't source anything but here is an SLBM test done in 2021 by a sub off of Florida, and it landed in the South Atlantic. So they must have several different ranges, and possibly it's changed over time. https://missilethreat.csis.org/us-navy-test-fires-trident-ii...
https://www.thedrive.com/the-war-zone/34043/france-just-test...
Generally the logic is don’t launch on trajectories over land unless you have to. I believe all of the land based is ICBMs are still tested from vandenberg on the (most beautiful section of) California coast near Lompoc for the same reason. Vandenberg doesn’t have any deployed ICBMs, they all fly to kwaj for testing. Same reason nasa/spacex/seemingly everyone but China make it a goal to not have launches go over populated areas.
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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 guidan…
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.
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> How were they doing alignment in a hangar to start with, were these roofless hangars? I don't think so. You can read more about alignment in page 7, paragraph 10A-23 and the following pages. It'd usually involve using test equipment and manually inputting the current coordinates (e.g. heading, position, altitude, date/time, ...) into the system, from what I understand. Regardless, the paragraph I mentioned in my pr…
I wonder, however, whether it could track stars from the ground during the day. Might well only have worked at night.
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Former military aerospace engineer here. In my opinion it would only be worth it on long range strategic bombers such as the B-52. Fighters don't have the legs to fly far enough that celestial navigation becomes worth the added complexity. For other air mobility platforms like the C-130 or C-17 in my experience they do not include these features, as GPS, INS, and regular old "ask ATC for a vector" are usually good en…
Knew an old guy who was a navigator in C-130's back in the late 1960s. He used celestial navigation. You are probably right that this went away sometime in the 1970s. Damn, now I'm feeling old. I miss the stars.
I'm saying something different, which is that unlike the SR-71, the C-130 didn't and doesn't have an instrument that scans the sky and automatically determines where it is based on the constellations it can see.
I'm going to replay this from memory without googling it, just to keep the late 20th century air of some people swapping unverifiable facts in a pub: There was an old friend of my mother's, now deceased, who was a retired engineer. He claimed to be the guy who invented the 2-part tuna can, and was known for handing out end chunks of titanium castings left over from some business he ran. At any rate, he had a couple o…
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…
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...
I'm going to replay this from memory without googling it, just to keep the late 20th century air of some people swapping unverifiable facts in a pub: There was an old friend of my mother's, now deceased, who was a retired engineer. He claimed to be the guy who invented the 2-part tuna can, and was known for handing out end chunks of titanium castings left over from some business he ran. At any rate, he had a couple o…
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…
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