Spy satellite sensing

I have at least one friend who is very insistent that US spy satellites can effectively track individuals through infrared sensing (body warmth, as featured in some Harrison Ford flick a few years back). Is it true that we could locate all or most of bin Laden’s forces in Afghanistan this way?

Even if it could “track” individuals heat (which I don’t believe they can), how would you know who its looking at?

I had a teacher in high school who was in the Navy reserves and his job was decoding (think that’s the right term) satellite photos. There’s a lot of varibles involved in something like this. First of all, you have to know where to look. Second, there has to be a two degree (so he said, but he hinted that it might even be less) tempature difference in the object and its surroundings for it to be visible. If Bin Laden were to go into a house, or stand inside a tent on a day when it was 98 degrees F, we couldn’t “see” him. Also note that things like heavy clouds (not that there’s much chance of those forming over Afghanistan), clothing, and ambient tempature can prevent someone from showing up. So, yes, we could do it, but there’s so many variables involved that its unlikely. We’d be better off trying to spot him using plain old spy sat photos than we would infrared ones.

No, we can’t locate military forces this way.

I can’t believe for a second that the IR signal from a human body would be able to penetrate the atmosphere to enable it to be dtected by a satellite thousands of miles up. IR light tends to be very easily disspated so you need resonably large sources to generate an IR or NIR sattelite image. However I’m not a physicist so maybe it is possible. However it wouldn’t be possible with cloud cover, it wouldn’t work if the surrounding ground were anywhere near 37[sup]O[/sup]C (ie any warm day) and it wouldn’t work under various other conditions. IR wouldn’t be the frequency of choice for following people.

Added to this to pick up an individual person your image resolution would need to be fantastic, and hence your footprint would be tiny. You could never sweep the whole of Afghanistan this way, so you’d need a person on the ground telling you were to focus the camera. That sort of defeats the whole purpose of the excercise doesn’t it? Then of course if the people climbed into trucks parked under cover and went separate directions what do you do? Which trucks do you follow? How many of these super spy sattelites have we got? The technique might have applications in terms of spotting defenders prior to a military advance on specific locations, but it wouldn’t be useful for scanning whole countries.

And of course bernse has already pointed out the other huge problem. How the hell do you tell if the red blob is bin Laden himself, or simply a goatherd?

The idea would be to single out all humans in the remote areas of Afghanistan, not to identify them beyond their mere existence, and to then methodically investigate all contacts. In that context, however, Gaspode’s observations are particularly apt.

The Keyhole and Improved Crystal series of satellites:

The article doesn’t mention tracking people, but based on what it does say, that doesn’t seem outlandish. Innnnteresting…
The Defense Support Program (DSP) is a series of satellites intended to work in infrared to detect the plumes from missile launches. From the link:

Not really on topic, I guess, but cool.