Ground Truth - Satellite Calibration Targets

At the end of the 1950's the CIA launched a series of strategic reconnaissance satellites in order to spy on the USSR. The satellites were used between 1959 and 1972 to carry out photographic surveillance of the Soviet Union, the People's Republic of China and other areas of interest to the United States.

In order to calibrate the cameras on board the reconnaissance satellites a series of calibration targets were built in the desert around Casa Grande, Arizona. These targets were used to test the focus and resolution of the imagery captured by the spy satellites.The calibration targets in Arizona consisted of 272 concrete markers arranged in a 16 by 16 mile square grid. Many of these calibration targets still exist today.

You can explore the remaining calibration targets in Arizona on a new art project called Ground Truth. For the project artists Julie Anand and Damon Sauer took photographs of the remaining calibration targets. On top of these photographs they have mapped the locations of present day satellites to 'emphasize the ubiquity of this contemporary technology encircling the globe'.

Ground Truth includes an interactive map which shows the locations of all the original 272 markers. On this map the lighter markers indicate the remaining calibration targets which have been photographed (click on the marker to view the photo). If you click on the darker markers you can view satellite imagery of the area where the original calibration target was located.