

Secret No More: Spy Satellite Designer Reveals Life's Work - bdr
http://www.space.com/13287-secret-spy-satellite-designer-reveals-lifes-work.html

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eps
I remember seeing a photo snapped by a 70s spy satellite that showed a guy
lying on a beach and the time on his wristwatch clearly visible. _1970s_.
Makes one really wonder where things are at now.

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arethuza
I suspect that was unlikely to have been a satellite shot - even the best
resolutions I have seen claimed are still around 5cm to 10cm - which is
nowhere near close enough to resolve the time on a wristwatch.

<http://en.wikipedia.org/wiki/KH-8>

<http://en.wikipedia.org/wiki/KH-9_Hexagon>

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iwwr
It should be a relatively simple problem of mechanics and optics. How big
would the spy camera have to be to capture that level of detail? Assuming say,
a budget of $500mil to 1bn per satellite.

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arethuza
Someone does a calculation in this discussion:

[http://www.natscience.com/Uwe/Forum.aspx/physics/10830/Maxim...](http://www.natscience.com/Uwe/Forum.aspx/physics/10830/Maximum-
resolution-of-spy-satellites)

That suggests that the max resolution from 850km (which does appear to be the
relevant height) of a 4m as 10cm. So for 1mm resolution, which would be about
right to resolve the time an a watch, you'd need at _least_ a 400m mirror,
probably much larger.

So $1 billion wouldn't be anything like enough.

[Apologies to anyone who actually knows about optics.]

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raldi
By my math, there was only enough film in the satellite for five hours of
continuous shooting. So I guess it sat dormant most of the time, and was only
activated when there was serious intelligence need?

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weaksauce
well the video said up to 70 inches per second and there were 4 film recovery
bays that would eject the pods of undeveloped film for a midair recovery by a
plane.

Assuming the video is correct and that the article is wrong, that would be ~15
hours per roll of film for a total of around 60 hours of continuous shooting.

I would imagine that they only used it for short bursts of filming to get high
value places of interest.

