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The SR-71 Blackbird Astro-Nav System worked by tracking the stars

theaviationgeekclub.com

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Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#261

Post by helpfulContrib »

jonathankoren wrote: post #258
irjustin wrote: post #248

Earlier quoted context omitted.

I wonder if the parent is talking about pure EMP without the nuke because those are pure fantasy. Kill all electronics w/o all the fallout.

No. That’s not what I mean. I’m talking about big boogeyman of an EMP attack that destroys the either the North American electrical grid and assorted electronics or merely all electronics in a city. There is no nonnuclear EMP weapon. Every proposed EMP attack is literally a hydrogen bomb delivered via an ICBM and detonated at extremely high altitude. That is the only way to deliver one to the proper place and the onl…

>There is no “fallout free” EMP.

False. There are non-Nuclear EMP's, and the USA even has a bit of experience with the Russian variants ..

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#262

Post by TTorler »

jonathankoren wrote: post #258
irjustin wrote: post #248

Earlier quoted context omitted.

I wonder if the parent is talking about pure EMP without the nuke because those are pure fantasy. Kill all electronics w/o all the fallout.

No. That’s not what I mean. I’m talking about big boogeyman of an EMP attack that destroys the either the North American electrical grid and assorted electronics or merely all electronics in a city. There is no nonnuclear EMP weapon. Every proposed EMP attack is literally a hydrogen bomb delivered via an ICBM and detonated at extremely high altitude. That is the only way to deliver one to the proper place and the onl…

> literally zero nuclear weapons have been detonated at high altitude https://en.wikipedia.org/wiki/Starfish_Prime

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#263

Post by raaaaraaaaa »

helpfulContrib wrote: post #256
jonathankoren wrote: post #237

Earlier quoted context omitted.

EMPs are a fantasy. Absolutely and unreservedly a complete fantasy. ZERO have ever been tested, and there’s literally a better use for a nuclear warhead. Not only is it a a completely hypothetical attack, it would look identical to a normal nuclear ICBM attack, and absolutely would result in a traditional retaliatory attack. Why would anyone trade an EMP for all their cities? Literally doesn’t make sense. No one in t…

>EMPs are a fantasy. The Defense Department doesn't agree with you one bit. Russia is the worlds leader in Non-Nuclear EMP/RFW systems: https://apps.dtic.mil/sti/trecms/pdf/AD1124730.pdf Non-nuclear EMP weapons are a thing.

In past two years we learned a lot about hi-tech Russian capabilities :D

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#264

Post by mnw21cam »

dekhn wrote: post #150
13of40 wrote: post #101

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…

the "quartz crystals" were likely optical flats and they were connected by wringing-on (like a set of gauge blocks). https://en.wikipedia.org/wiki/Optical_flat#Wringing I'm not sure why you'd use an optical flat in a missle nav system, now I'm curious.

Any window that a telescope is looking through will need to be optically flat, otherwise it will totally mess up the ability of the telescope to get a clear image.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#265

Post by helpfulContrib »

raaaaraaaaa wrote: post #263
helpfulContrib wrote: post #256

Earlier quoted context omitted.

>EMPs are a fantasy. The Defense Department doesn't agree with you one bit. Russia is the worlds leader in Non-Nuclear EMP/RFW systems: https://apps.dtic.mil/sti/trecms/pdf/AD1124730.pdf Non-nuclear EMP weapons are a thing.

In past two years we learned a lot about hi-tech Russian capabilities :D

We didn't, and thats the point.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#266

Post by KaiserPro »

hbarka wrote: post #232

Off tangent here but I thought I'd mention that yesterday a replica of a traditional Polynesian ocean-going canoe, the Hokulea, sailed into San Francisco, navigated with non-instrument methods including star observations. https://www.sfchronicle.com/bayarea/article/hokulea-polynesi... The Hokulea's maiden voyage was in 1975 and since then it has made global voyages to demonstrate and preserve ancient Polynesian wayfi…

Polynesian navigation is Wild.

I think its well known that it almost died out, as its something that needs ideally to be taught in the (sea) field.

However there are now people in their 30s who can navigate by the stars, sound, wave shape and pattern, cloud layout and birds https://manoa.hawaii.edu/exploringourfluidearth/physical/nav...

Similarly there are people who can navigate the desert, even though the dunes are mostly ever shifting.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#267

Post by [deleted] »

TTorler wrote: post #262
jonathankoren wrote: post #258

Earlier quoted context omitted.

No. That’s not what I mean. I’m talking about big boogeyman of an EMP attack that destroys the either the North American electrical grid and assorted electronics or merely all electronics in a city. There is no nonnuclear EMP weapon. Every proposed EMP attack is literally a hydrogen bomb delivered via an ICBM and detonated at extremely high altitude. That is the only way to deliver one to the proper place and the onl…

> literally zero nuclear weapons have been detonated at high altitude https://en.wikipedia.org/wiki/Starfish_Prime

[deleted]

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#268

Post by mnw21cam »

dekhn wrote: post #157
blackhaz wrote: post #20

Earlier quoted context omitted.

OK. Now please do the same with a Z-80 class CPU.

In my experience, if there was a well-defined problem in the 70s or 80s, some clever person came up with a workable solution using a tiny microprocessor with limited RAM. The way I think about it is... when I was a kid I hated waiting at lights and imagined you could build a computer vision/ML system (this was in the '80s) that coudl recognize traffic and change the light to green when it was safe, rather than timing…

And then someone rolls up with a bicycle, and because it doesn't have as much metal in it as the detector expects, they end up sitting at a red light forever. Been there, done that.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#269

Post by wnkrshm »

jonathankoren wrote: post #254
sonthonax wrote: post #252

Earlier quoted context omitted.

> Why would anyone trade an EMP for all their cities? ICMBs were a theoretical threat. Cold War doctrine had a more realistic (and less apocalyptic) WWIII that would be fought by tactical nukes and tanks through Europe.

Bullshit. They’ve been demonstrated. Repeatedly, and publicly. That’s the whole point of having them. Also, there is no difference between a tactical and strategic nuke from an escalatory perspective. Once the genie is out, it’s out.

There are people who argue that there are ways to keep limited nuclear warfare limited. [0] I think the RAND institute also published some study on it not outright rejecting the idea but I can't find it atm.

[0] https://www.sup.org/books/title/?id=21511

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#270

Post by hoseja »

titzer wrote: post #209
PNewling wrote: post #193

Earlier quoted context omitted.

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.

This is running into the no-code problem of clear-enough requirements being as complex as the code, via Kolmogorov.
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