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> the flight plan was recorded on a punched tape that told the aircraft where to go, when to turn, and when to turn the sensors on and off. This is equally fascinating to me. Before each flight, someone had to generate a flight plan and punch it onto a physical tape, then load it into the plan. T No mid-flight "re-calculating route" if stuff goes wrong. One of the most interesting and under-appreciated aspects of ear…
Simply amazed by the fact that something similar to "star trackers" as we know them today goes back to the 60s...
um, doesn't the sextant go back much much further than the 60s?
Earlier quoted context omitted.
The F22 had an unintentional problem of being unable to cross the international date line, which was discovered when attempting to fly from Hawaii to Japan. Given that it may very well be better to assume that anything untested doesn't work at all and to live within those restrictions.
The International Date Line and the 180-degree line of longitude have bitten a _lot_ of folks who don't think to test at the boundaries.
When I first heard of astro-nav (for missiles) I thought it was so future sounding, like star trek. But now that I do astrophotography regularly it's just another tool that I use. It's super simple to do, I can take a photo of the night sky, and if I know the focal length and pixel size of my camera I can figure out exactly where my telescope is pointed in seconds, with an accuracy 2.5 arcseconds. You can even do it…
OK. Now please do the same with a Z-80 class CPU.
From what I’ve read (mostly the excellent book “Inventing Accuracy” the main challenge is very precisely aligning the telescope with the “stable member” in the gyroscope.
ICBMs have used celestial guidance since the 50s. https://airandspace.si.edu/collection-objects/snark-guidance...
You can see one of these up close - both the device, and the airplane! - at the Evergreen Aerospace Museum in McMinnville, OR. They also have on display another Blackbird payload labeled DEF-H. It’s a nondescript white box which you are allowed to look at, but not allowed to know what it does. XD
Earlier quoted context omitted.
celestial navigation is 4000 years old
I think it is waaaay older. The north star and the southern cross probably guided humans since they had some sort of consciousness. If you see the night sky every night (without distracting screens), the shapes became kind of familiar.
So now you can see why Polaris will not always be aligned with the north spin axis of the Earth - because that axis is slowly changing the direction in which it points (precession)! Right now, the Earth's rotation axis happens to be pointing almost exactly at Polaris. But in the year 3000 B.C., the North Star was a star called Thuban (also known as Alpha Draconis), and in about 13,000 years from now the precession of the rotation axis will mean that the bright star Vega will be the North Star.Interesting that it’s not confirmed if the SR-71 flew in the Southern Hemisphere. Would be a very bold design if it didn’t and the system wasn’t designed for it.
The F22 had an unintentional problem of being unable to cross the international date line, which was discovered when attempting to fly from Hawaii to Japan. Given that it may very well be better to assume that anything untested doesn't work at all and to live within those restrictions.
> the flight plan was recorded on a punched tape that told the aircraft where to go, when to turn, and when to turn the sensors on and off. This is equally fascinating to me. Before each flight, someone had to generate a flight plan and punch it onto a physical tape, then load it into the plan. T No mid-flight "re-calculating route" if stuff goes wrong. One of the most interesting and under-appreciated aspects of ear…
America was not critical defeating Germany. The soviets did this one.