JJ's Journal: Satelite Imagery

One thing I have been seeing a lot of talk on Slashdot about has been the satelitte imagery of Iraq. What one heck of a lot of people fail to comprehend is that there are two types of spy satelittes: geosynchronous and low-orbit ones.

When we hear talk of counting the hairs on someone's head or the like from orbit, it means from the latter. The problem is, nobody has more than a few (max 30) of these up at any one time and they constantly are falling back to Earth. That means they can't offer continuous coverage and when they are overhead can be plotted quite accurately. Recall the scene of IRA terrorists rushing into tents to be replaced by Libyans in the Libyan desert in "Clear and Present Danger". That was because a low-orbit satelitte was passing overhead.

Geosynch satelittes orbit much further out and are semi-permanent. They can continuosly watch one area, say Iraq, and keep a building under general surveillance, but not produce high detail pictures. They are great for where armies are or general activity level but they can easily be fooled at say following a single truck.

Normal intelligence gathering involves using the geosynchs to target the low-orbits, occasionally re-tasking them into different orbits with different peak observation times to catch the ground-bound bad guys off guard. Again, "Clear and Present Danger."