Also interesting are the resolution targets, using sets of black and white bars at varying widths in both X any X orientation, to determine the spatial resolution i.e. how high frequency a component could still be imaged separately as lines, similar to TV test cards. These are discussed in various blogs [1][2] with some amazing picures. I think these were for both satellite imaging and spy-plane (U2 and SR-71 plus less exotic surveillance systems) and not just the USA. This article [3] shows some satellite test targets in the Gobi desert, presumable for Chinese (PRC) spy satellites, and also has a cool picture of the world's largest compass rose, at Edwards dry lake bed, as well as explaining the crosses from the original article, and talking about radar altimeter targets (another dry-lake bed) that are mapped to centimetre accuracy in altitude for calibrating GPS and other systems.
I find it a really interesting area of industrial/scientific archaeology, with some fascinating stories.
Those tri-bar patterns are fascinating. I'd imagine that American surveillance equipment would be able to discern all but the smallest couple of squares.
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.
USSR "trolled" the US by painting windows on top of a plane or helicopter while it was under development. I can't remember the exact one will have a look around.
I'm sure I've also read about this, but can't find any links at the moment. The art of Maskirovka [1] (deception and camouflage) is still part of Russian military doctrine. Interestingly, the US also does something similar with planes like the A-10, which has a 'fake cockpit' painted on its underside, so that it is hard to determine the orientation of the aircraft visually. This is actually patented [2] and has been applied to various different aircraft, see the pictures accompanying this answer [3] on stackexchange.
According to wiki the one I was thinking of was the Ka-50
> The single-seat configuration was considered undesirable by NATO. The first two Ka-50 prototypes had false windows painted on them.[19] The "windows" evidently worked, as the first western reports of the aircraft were wildly inaccurate, to the point of some analysts even concluding its primary mission was as an air superiority aircraft for hunting and killing NATO attack helicopters.[20]
I don't think that even LEO Spy Satellites have that resolving power. Of course, that information would be classified. Does any HN reader know what a reasonable guess at their resolving power would be? I would love to know.
Commercial satellite imagery is available at 0.25m resolution these days, so assuming an order of magnitude better that gives around 2.5cm resolving power, or one inch. I think I've heard about 5cm quoted somewhere, as well. So, maybe just good enough to detect the difference between small-arms, and certainly enough to read identification markings on an aircraft, or to determine the name of the newspaper, but not to read its headlines.
I wonder what the real limit is for resolution, due to the distortion of the atmosphere.
I guess that by taking multiple photos in quick succession from slightly different points you could reconstruct a clearer image. It's not my field at all though, so I may just be randomly guessing.
It would be kinda fun to do these crazy scale things and have no reason to do them with the intention that our distant ancestors will be as confused as hell but then I look around at the modern world and think they'll no doubt think that anyway.
If you're into that kind of stuff, read Mark Lawrence's books. It's set in post-modern times where our civilization is known as The Builders. Complete with ghosts coming out of unintelligible machines and talking about how stupid everyone is these days.
My dad was project photogrammetrist on Corona when he worked at Itek in the 60s. Lots of stories around focus and aiming challenges, since Corona was used to build maps of inaccessible regions of the world (e.g. Soviet Union ICMB sites). Focus targets gave high contrast, known images to detect what kind of focus problems were being encountered -- ranging from image smear from forward motion compensation failing or stretching the film; film sticking, stretching and/or lifting off of the focal plane; star camera inaccuracies; thermal distortion of camera, spacecraft, star camera, or film; etc. A few good books on Corona (https://www.cia.gov/library/publications/intelligence-histor...) and Itek (https://books.google.com/books/about/Spy_Capitalism.html) out there. Same teams worked on subsequent KH projects (Gambit, Hexagon/Big Bird/BMF), as well as Apollo and Viking camera systems.
It's known as industrial or scientific archaeology [1] and is a fascinating area of study. I found a good book on it, called 'Industrial Archaeology: Future Directions' [2] which most university libraries should have.
Interesting story and cool photos. Couldn't get to the end due to website design issues. Were these for horseback delivery or for airplanes?
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.
Air mail. These were the days before good roads crossed the country, and where even an automotive trip was an Adventure which would take weeks. Horseback, you're going slow enough that you'd be able to see much smaller signs, and would be on a pretty well-trod path.
Shortly thereafter, though, a few things happened that made the arrows pretty obsolete. Mapping of course, was a big one; you could now navigate a lot more reliably through unknown territory. More importantly, a network of radio beacons was set up. Charts had lists of radio beacons, with their frequencies. Pilots could tune in to hear them repeatedly chirp their identification in morse code, and use radio direction finders to set their heading accordingly.
There's one other feature that was developed in that time period which also made pilots' navigation job a lot easier. The federal highway system meant that there were good, very visible, roads, serving as routing beacons in their own way. Pilots would, and still do for a lot of general aviation planes, route close to highways, because they're also a very obvious landmark that carves a path through the country.
For the air mail planes that used to fly through the night. Most of those arrows were painted in luminescent paint, and had a light tower nearby shining down on it so that the arrow glowed and was highly visible to the poor cold, tired mail plane pilot above.
They did have compasses, but those do not give you your position. So if you've been flying for four hours at night, with a thirty mph wind, you could be 120 miles away from where you planned on being. You need some way of getting an absolute position, which these provided.
Windspeed is not unlike ocean currents, but since the speeds involved are a lot higher than in a boat errors in estimation accumulate way more quickly.
Not without aviation charts, which the article does mention were in short supply back in the early days of aviation. That, and I'm willing to bet that the licensing for pilots less than twenty years after the Wrights took off at Kitty Hawk was less than rigorous. So assuming that a licensed pilot, if such a thing even existed, was well-versed in navigation via charts and a compass was likely wrong.
Another question of course is that since it was impossible to load the cameras with new film, how much film did they carry when deployed? After using it all the camera was useless.
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.
> Another question of course is that since it was impossible to load the cameras with new film, how much film did they carry when deployed? After using it all the camera was useless.
That's why both the US and Russians experimented with military space stations (US MOL, Soviet Almaz), so they could both resupply the cameras with more film, and in emergencies develop it directly in space and radio down scans of them.
However, both eventually figured out how do automate the latter and eventually developed fully digital cameras, rendering manned surveillance stations obsolete. The US never launched any, and the Soviet program was cancelled after three stations (that were masked as Salyuts).
> BTW were those Corona satellites guidable, or did they just fly wherever they flew and operators could ask them to photograph what was under?
Satellite orbits are largely fixed – changing your orbital plane is the single most expensive manoeuvre you can do, and too expensive in practice. (Even if we wanted to, we couldn't tilt the ISS' orbit by more than a degree or two, and if we did, Soyuz rockets couldn't reach it any more.)
That's why we instead just launch a whole lot of satellites that focus on different areas.
> 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
Even just lowering your orbit is expensive, fuel-wise, but the more important problem: The lower you go, the faster you are. This means lower exposure times and less image quality, not more.
Additionally, as far as I can tell, the film buckets were really dumb and used solid boosters hand-tuned to their original orbit. Launching them from a different trajectory would likely make them burn up during re-entry.
The Corona project. A/K/A the KeyHole satellites. If my count is right, 135 satellite launches, though not all were successful.
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.
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.
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....
Thanks. I was curious about that as I'd heard the term used and was almost certain the context was more recent than the Corona project (1972 end date).
I'm also curious about Keyhole and the project, similarly named, which become Google Earth.
Anyone know what's nearby there at about (32.92669, -111.922201)[0]? It looks like some sort of strip mine a few hundred feet to the north, so I assume it's related, but was just curious what it is. It looks like a painting!
As e2021 said, these are some kind of tailing dams to treat remaining water from mining.
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
Looks like a tailings dam to me, containing waste materials from the mine after processing. The solution has partially evaporated leaving a salt residue.
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...
Looks like some kind of debris pile, perhaps from the mine. The corners are angled like it's building up to an eventual truncated pyramid shape, and the one in the upper left looks higher, and "finished" compared to the other three. There's a similar pile that isn't laid out as a square just south of the mine, you can see the multiple layers getting smaller as it gets higher.
They're spaced out over miles, so presumably they'd take a wide shot of a bunch of them and check that the focus on one side of the frame to the other would be consistent.
They took a whole series of images at different focuses, then dropped it to earth and people radioed back the most in-focus setting....is how I'd do it.
Well, I'm going to assume there was no actual "computer" on board...
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.
If you had an image taken by the satellite and the time the image was taken, then yes. Google maps doesn't make it obvious but not all satellite images are taken from directly overhead. Most are off angle, so by calculating the distance on the film between known points on the earth, you could have a pretty good idea of the location of the satellite.when the picture was taken.
I don't think so, since they'll cover all (or nearly all) of the earth the information that a satellite at an unknown time could see this spot doesn't tell you much.
Right. Since each "mysterious" X was equipped with a "US Army Corps of Engineers" brass plate, it was kind of obvious they were calibration targets for something military. The article says "focusing", but they were probably used to get more precise orbital elements for satellites. This was pre-GPS, and calibration across geography on a planetary scale was tough.
> The article says "focusing", but they were probably used to get more precise orbital elements for satellites. This was pre-GPS, and calibration across geography on a planetary scale was tough.
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:
The description there implies that the other crosses no longer remain, but I was able to find the first 3 I looked for just by looking for midpoints between other markers on the grid.
> "This [X] we're standing on right now helped protect us from nuclear war," Owen says.
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.
I mean, isn't that a bit pedantic? If you go down that route, MAD didn't keep us safe either, it's our enemies belief/knowledge that we had weapons of mass destruction, that kept us safe. etcetcetc
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".
They could have embedded LOVE instead of X's and it wouldn't have created any mystery and unneeded attention, as everyone would know it was hipsters.. no, I mean hippies.. =D
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...