"The KH-9 would image a wide swath of terrain, later scrutinized by imagery analysts on the ground for so-called ‘targets of opportunity.' Once these potential targets were identified, a KH-8 would then be maneuvered to photograph the location in much higher resolution."
This is "0.5m" resolution (from GeoSat-1).
http://geoeyemediaportal.s3.amazonaws.com/assets/images/gall...
As several comments above have pointed out, Google Maps misleads the public by referring to aerial photos taken from airplanes as a "satellite" view of the ground. Studying imagery of my own neighborhood on Google Maps makes clear that the images at close-in views must come from airplanes. The particular walking path I take from my house to the local public library is very clearly visible, but again there is no hope of reading automobile license plates from those photographs.