Corona Satellite Calibration Targets, Cold War calibration site in Casa Grande, Arizona, US.
The Corona Satellite Calibration Targets are a grid of white concrete Maltese crosses spread across the desert landscape near Casa Grande. Each cross was designed as a reference marker for aerial photography and precise ground verification.
The US Army Map Service created this test range in the 1960s to validate aerial survey cameras and improve mapping technology. The site was designed to calibrate surveillance satellites and ensure the accuracy of their imagery.
The concrete crosses represent how Americans developed new ways to map and monitor land from the air during a time of global tension. These markers show the importance that precision mapping held for military planning and defense strategies of that era.
Two of the original crosses remain visible at the intersections of South Montgomery and West Cornman Roads, and at West Cornman Road and Carmel Boulevard. Plan to visit during early morning or late afternoon when the light helps reveal the weathered concrete markers.
Groundwater extraction for farming caused the land to subside, gradually shifting many of the concrete markers from their precise positions. This natural settling made the site less useful for its original purpose as the alignment drifted over time.
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