# Spy satellite sensing **URL:** \ **Category:** Factual Questions\ **Created:** [September 24, 2001, 11:48pm UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586 "2001-09-24T23:48:04Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Rob\_Blakeney](https://avatars.discourse-cdn.com/v4/letter/r/e9a140/32.png) [@Rob\_Blakeney](https://boards.straightdope.com/u/Rob_Blakeney)\ **Post date:** [September 24, 2001, 11:48pm UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/1 "2001-09-24T23:48:04Z")
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? ---
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [September 24, 2001, 11:55pm UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/2 "2001-09-24T23:55:45Z")
Even if it could “track” individuals heat (which I don’t believe they can), how would you know who its looking at? ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [September 25, 2001, 1:54am UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/3 "2001-09-25T01:54:40Z")
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. ---
**Author:** ![Gaspode](https://avatars.discourse-cdn.com/v4/letter/g/aeb1de/32.png) [@Gaspode](https://boards.straightdope.com/u/Gaspode)\ **Post date:** [September 25, 2001, 2:04am UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/4 "2001-09-25T02:04:47Z")
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? ---
**Author:** ![Rob\_Blakeney](https://avatars.discourse-cdn.com/v4/letter/r/e9a140/32.png) [@Rob\_Blakeney](https://boards.straightdope.com/u/Rob_Blakeney)\ **Post date:** [September 25, 2001, 3:32pm UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/5 "2001-09-25T15:32:43Z")
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. ---
**Author:** ![Kamandi](https://avatars.discourse-cdn.com/v4/letter/k/5daacb/32.png) [@Kamandi](https://boards.straightdope.com/u/Kamandi)\ **Post date:** [September 25, 2001, 4:28pm UTC](https://boards.straightdope.com/t/spy-satellite-sensing/83586/6 "2001-09-25T16:28:16Z")
The [Keyhole and Improved Crystal](http://www.fas.org/spp/military/program/imint/kh-12.htm) series of satellites: > [@](#): > > operate in visible and near infrared light, as well as thermal infrared to detect heat sources. These sensors probably incorporate low-light-level image intensifiers to provide night-time images. The KH-12’s have an infrared capability superior to that of the IMPROVED CRYSTAL, with the advantage in infrared primarily for camouflage detection, for looking at buried structures, for looking at differential thermal inertia in the target area, for trying to determine which factories are operating and which factories are not. > > The IMPROVED CRYSTAL’s sophisticated electronics provides sharper images than the KH-11, comparable in quality to the best of the film return satellites, with a resolution approaching ten centimeters. 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)](http://www.fas.org/spp/military/program/warning/dsp.htm) is a series of satellites intended to work in infrared to detect the plumes from missile launches. From the link: > [@](#): > > The sensor’s purpose is to detect, locate, and identify targets of interest that are intense sources of IR radiation. Not really on topic, I guess, but cool.