There is not a square-inch of earth that has not been photographed and mapped by satellites today.
Arriving at this level of technological brilliance was no small matter.
By the summer of 1957, US military officials realized that they needed something better, something smarter.
A U.S. Air Force airplane recovers a Corona Capsule returned from Space.
In October 1957, the Soviets launched the first artificial satellite Sputnik.
The technology used in the Corona program were state-of-the-art.
The cameras, made by defense contractor Itek, were humongous.
The lenses were 12 inch long and 7 inch in diameter, but the cameras were 5 feet long.
Later models were larger still, at 9 feet in length.
The first Corona satellites had a single camera, but a two-camera system was quickly implemented.
Both cameras were tilted by 30 degrees, so that they could record stereoscopic images.
This allowed cartographers to determine terrain relief.
Later in the program, a third camera was added.
These cameras could resolve images on the ground down to 40 feet.
Some missions achieved resolutions down to 3 feet, nearly at par with satellites today.
This was partly because the satellites orbited much closer to the earths surface, at 100 miles.
Some of the later missions orbited even lower, at 75 miles.
Each of the 267 crosses were 60 feet across, and together they covered an area 16 miles square.
About half of these markers still exist today.
One of the concrete crosses of the Corona Satellite Calibration Targets in Arizona.
Image credit:Marine 69-71/Wikimedia Commons
Close-up view of the Corona Satellite Calibration Target.
Engineers from General Electric devised a reentry capsule nicknamed film bucket that was jettisoned from the satellites.
In case theaircraft missed, the capsule was designed to float.
This was to prevent the enemy from capturing the film.
The Hollywood-esque retrieval procedure did not always work.
The parachute lines were used as horse harness.
Photos of the capsule, emblazoned with the words United States and Secret, appeared in a local newspaper.
The Corona program ran for thirteen years, from June 1959 to May 1972.
During this period, the satellites collected over 800,000 images photographing 520 million square miles of foreign territory.
In short, the program was a staggering success.
CORONA reconnaissance satellite photograph of the Lop Nur Nuclear Test Base in Xinjiang, China.
The photograph was made on October 20, 1964, four days after China conducted its first nuclear test.
A detail shows the an enlargement of the Kremlin.
Visible in the photograph are two squadrons of Tupolev Tu-16 “Badger” bombers.
Image credit:Smithsonian National Air and Space Museum
