Starting operation since 1959, spies in the Corona program helped the United States collect more than 800,000 photos of 1,346 million km2 of foreign territories for more than a decade.
Design of Corona satellite. Image: VICE
In October 1957, the first Soviet Union launched the artificial satellite Sputnik. 8 weeks later, engineers from the US Air Force, ARPA (senior research project) and the CIA met and decided to make the first US spy satellite named Corona. To cover the true purpose, this confidential program is called by another name “Discoverer” and described as a scientific research program.
The technology used in the Corona program is very modern. Each Corona satellite uses a special 70 mm film produced by Eastman Kodak, placed in a special camera equipped with a 610 mm long focal length lens. The camera made by ITEK defense contractor is very massive. The lens is 30 cm long and has a diameter of 18 cm but the camera is 1.5 meters long. The following versions are even larger, 2.7 m long. Corona satellite initially carried a film of nearly 2.4 km with each camera, but in the fifth generation of satellite, the figure doubled to nearly 4.8 km with each camera.
The first Corona satellites have a camera, but the two camera system is quickly applied. Both cameras are tilted 30 degrees to be able to take 3 -dimensional photos. This allows experts to draw a map to determine topography. At the end of the program, a third camera was added. These cameras can clearly capture up to 12 m large objects on the ground. When the program progresses and ripe technology, the camera can observe small details up to 1.5 meters. Some tasks achieve a resolution of up to one meter, close to today’s satellite. This is partly compared to the flying satellite in the orbit closer to the Earth’s surface, 160 km from. Several missions even operate in lower orbit, only 120 km.
Camera stability and keep them focus on the ground while flying at 28,000 km/h is not an easy task. In order to adjust the camera from the universe, a network of 267 giant concrete bars was built on the desert around Casa Grande, Arizona. Each bar is more than 18 m wide, covering the area of 41.4 km2. About half of this mark still exists today.
The most weird thing in the Corona program is the way to transfer photos to Earth. Different from digital photos directly transmitted images from satellites via radio waves, the Corona program uses films with mechanical machines developed and printed.
The General Electric engineers create a book cavity nicknamed the “movie” shot from the satellite. The film shutter compartment is equipped with a heat shield separated at an altitude of over 18,000 m after the book and the umbrella. It will be attached to a plane flying across the air. In the case of a sliding aircraft, this compartment is designed to float for two days before sinking. However, after a few incidents, the US Air Force decided to stop labeling “secret” on the train compartment, instead they issued a notice in 8 languages promising to give bonuses to the founder and return the film.
The Corona program lasted 13 years from June 1959 to May 1972. During this time, the satellite collected more than 800,000 photos of 1,346 million km2 of foreign territory. The program was kept secret for more than two decades until President Bill Clinton ordered the 1995 program.