I find it a really interesting area of industrial/scientific archaeology, with some fascinating stories.
[1] http://www.clui.org/newsletter/winter-2013/photo-calibration... [2] http://www.bldgblog.com/2013/02/optical-calibration-targets/ [3] http://www.atlasobscura.com/articles/landscapes-made-for-sat...
Totally in the middle of nowhere, and quite amazing to see.
They'd easily be able to read registration numbers on aircraft, probably almost be able to discern specific small arms (e.g. count the number of RPGs and AK-47s sitting on some tarmac somewhere). Amazing.
http://www.cntraveler.com/stories/2013-06-17/transcontinenta...
I also find these kind of things cool. Forgotten structures that once served an important roll but now are mostly forgotten.
[1] https://en.wikipedia.org/wiki/Industrial_archaeology [2] http://www.springer.com/gb/book/9780387226088
Terrible, terrible UX in the form of a jittery delayed popover that fills the entire phone screen. If you are going to do this (and I can't stand the fact that it actually works on many people), make it so easy to dismiss and fast to load that I close it instead of instictively hitting back.
So how'd they get that film back down from space?
A modern digital camera would have been really valuable for these purposes.
BTW were those Corona satellites guidable, or did they just fly wherever they flew and operators could ask them to photograph what was under?
A useful way to decommission a satellite that is about to run out of its film storage would have been to guide it to a trajectory where it can take more accurate pictures from a lower position -- because once the satellite goes on such a trajectory, it will soon come down completely. But if you could use the last bit of film that way, and eject it for retrieval, then the dying of the satellite would at least have been utilized.
Fun fact: this was the early 1960s. CCD technology and IP transmission bitrates were a bit primitive[1], so the film cameras would eject capsules after they'd been shot, which would re-enter the atmosphere and be recovered, most through mid-air retrieval. The project was active from 1959 to 1972.
https://en.m.wikipedia.org/wiki/Mid-air_retrieval
https://en.m.wikipedia.org/wiki/Corona_(satellite)
Video of recovery: http://petapixel.com/2014/08/31/us-spy-satellites-used-drop-...
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Notes:
1. Well, technically they didn't exist.
I suspect something like X.25 is used instead for digital data, if not something even more bespoke... and many satellites still send analog data.
For example, this is the protocol used for NOAA weather satellites (and actually was developed in the 60s): https://en.wikipedia.org/wiki/Automatic_picture_transmission
I know little about space data transmission (though I vaguely recall some good discussion around the time of the New Horizons Pluto contact), but yes, it's been a mix of analog transmissions (initially) and digital, of various descriptions. I believe there is an IP-based transmission support for the ISS, though I wouldn't swear to that.
One of the zaniest image transmission protocols was for the early Soviet lunar missions, Luna 3. Again, film cameras, an in-spacecraft photo processing lab, and a TV camera to read off the film image and transmit it back to Earth. The image quality wasn't much, but it was the first imagery of the Lunar farside ever received.
https://en.m.wikipedia.org/wiki/Luna_3
A few years back there was a story of the National Geographic lunar map timed to coincide (well, a month late) with the December, 1968, Apollo 8 mission, the first manned flight around the Moon (though without a landing). This gave us the famous Earthrise photograph, and the Christmas Day broadcast from Apollo. The story of the map, and how rapidly the Lunar far side went from terra incognito (well, luna incognito) to mapped in detail was pretty staggering. I had that map as a kid, and just figured "we knew all that". Sometimes it takes growing up to see things with childlike wonder....
The story:
http://kelsocartography.com/blog/?p=1481
http://kelsocartography.com/blog/?p=1588
(Pretty sure that's made HN at some point.)
I'm also curious about Keyhole and the project, similarly named, which become Google Earth.
[0] http://maps.apple.com/maps?ll=32.926699,-111.822201&spn=0.00...
Google even has streetview photos from the nearby road, resolution is just enough to read "[something] wastewater evaporation ponds" on the fence sign: https://goo.gl/maps/WZKbdPxs5sS2
The mine itself looks cool, too: https://www.google.cz/search?q=Casa+Grande+Copper+Mine&safe=...
At least thats what it looks like to me. I don't think its a raised pyramid like the other reply says, pretty sure it is a hole.
If you do a google image search for 'tailings dam' you see some things that look pretty similar...
Think of it as an eye chart for satellites.
These were film cameras, so the computer on board can't look through the camera and see if the objects are in focus, can they?
However, a sharply focused image has more high-frequency components than a poorly focused one, so some sort of frequency discriminator (a technology from the 1920's IIRC) could possibly suffice to check and adjust focus. Remember that we've had sophisticated servomechanisms since WW2 so the feedback theory to do this was already well known.
But that's just a guess...
https://drive.google.com/open?id=1bebA9E6kTb3G9g5GEeezYPzvwH...
Based on the map from wikipedia, which had 84 locations, this has 120.
My guess is that they served a function for calibrating ground control points rather than orbital elements. Even today, NORAD publishes orbital elements (TLEs) for spacecraft deduced by radar (and also optical means). I think other radio ranging techniques were also used before GPS. Trying to point at Earth-fixed point with only an inertial attitude (without a position/velocity) seems really tough.
Today, lots of CubeSats don't have GPS, so they eagerly await getting TLEs from NORAD. It seems like this Twitter is always the first with new data:
It's not too long IMO and the human element of the story is lost in this summary.
Um no. It just helped the US know where shit is. They didn't keep us safe. Mutually assured destruction did. That's why every war since then has been a proxy war.
If anything, programs like this poured massive amounts of money into expanding out out of control military and probably caused the expansion of wars into areas, leading to the deaths of countless civilians in the former USSR nations.
It's all part of it. Without intelligence (from dozens of source) to act upon, and Americas enemies believing we could find meaningful targets and/or hit them, MAD wouldn't really exist. Same goes for not having the tech to launch the nukes. Or a hundred other things.
It all helped, to one degree or another, and that is all they said. "This [X] we're standing on right now helped protect us from nuclear war".
Am i missing your point?
Yes, good luck and good timing, but still - ha!
