Corona ( satellite ) The Corona program was a series of American strategic reconnaissance satellite s produced and operated by the Central Intelligence Agency Directorate of Science & Technology with substantial assistance from the U . S . Air Force . The Corona satellites were used for photographic surveillance of the Soviet Union ( USSR ) , the People ' s Republic of China , and other areas beginning in June 1959 and ending in May 1972 . The name of this program is sometimes seen as " CORONA " , but its actual name " Corona " was a codeword , not an acronym . The Corona satellites were designated KH - 1 , KH - 2 , KH - 3 , KH - 4 , KH - 4A and KH - 4B . KH stood for " Key Hole " or " Keyhole " ( Code number 1010 ) , with the name being an analogy to the act of spying into a person ' s room by peering through their door ' s keyhole . The incrementing number indicated changes in the surveillance instrumentation , such as the change from single - panoramic to double - panoramic cameras . The " KH " naming system was first used in 1962 with KH - 4 and the earlier numbers were retroactively applied . There were 144 Corona satellites launched , of which 102 returned usable photographs . History and costs . Corona started under the name " Discoverer " as part of the WS - 117L satellite reconnaissance and protection program of the US Air Force in 1956 . The United States Air Force credits the Onizuka Air Force Station as being the " birthplace of the Corona program . " In May 1958 , the Department of Defense directed the transfer of the WS - 117L program to Advanced Research Projects Agency . In FY1958 , WS - 117L was funded by the AF at a level of US $ 108 . 2 million ( inflation adjusted US $ billion in ) . For Discoverer , the Air Force and ARPA spent a combined sum of US $ 132 . 3 million in FY1959 ( inflation adjusted US $ billion in ) and US $ 101 . 2 million in FY1960 ( inflation adjusted US $ billion in ) . The Corona project was pushed forward rapidly following the shooting down of a U - 2 spy plane over the Soviet Union in May 1960 . Technology . The Corona satellites used special 70 millimeter film with a focal length camera . Manufactured by Eastman Kodak , the film was initially thick , with a resolution of 170 lines per of film . The contrast was 2 - to - 1 . ( By comparison , the best aerial photography film produced in World War II could produce just 50 lines per of film . ) The acetate - based film was later replaced with a polyester - based film stock that was more durable in earth orbit . The amount of film carried by the satellites varied over time . Initially , each satellite carried of film for each camera , for a total of of film . But a reduction in the thickness of the film stock allowed more film to be carried . The amount of film carried was doubled ( both by reductions in film thickness and by the addition of additional film capsules ) by the time the fifth generation of the satellite ( the KH - 5s ) was built , to of film for each camera for a total of of film . Most of the film shot was black and white . Infrared film was used on mission 1104 , and color film on missions 1105 and 1008 . Color film proved to have lower resolution , however , and was never used again . The cameras were manufactured by the Itek Corporation . A , f / 5 triplet lens was designed for the cameras . Each lens was in diameter . They were quite similar to the Tessar lenses developed in Germany by Zeiss . The cameras themselves were initially long , but later extended to in length . Beginning with the KH - 4 satellites , these lenses were replaced with Petzval f / 3 . 5 lens . The lenses were panoramic , and moved through a 70° arc perpendicular to the direction of the orbit . A panoramic lens was chosen because it could obtain a wider image . Although the best resolution was only obtained in the center of the image , this could be overcome by having the camera sweep automatically ( " reciprocate " ) back and forth across 70° of arc . The lens on the camera was constantly rotating , to counteract the blurring effect of the satellite moving over the planet . The first Corona satellites had a single camera , but a two - camera system was quickly implemented . The front camera was tilted 15° forward , and the rear camera tilted 15° aft , so that a stereoscopic image could be obtained . Later in the program , the satellite employed three cameras . The third camera was employed to take " index " photographs of the objects being stereographically filmed . The J - 3 camera system , first deployed in 1967 , placed the camera in a drum . This " rotator camera " ( or drum ) moved back and forth , eliminating the need to move the camera itself on a reciprocating mechanism . The drum permitted the use of up to two filters and as many as four different exposure slits , greatly improving the variability of images that Corona could take . The first cameras could resolve images on the ground down to in diameter . Improvements in the imaging system were rapid , and the KH - 3 missions could see objects in diameter . Later missions would be able to resolve objects just in diameter . A single mission was completed with a resolution but the limited field of view was determined to be detrimental to the mission . resolution was found to be the optimum resolution for quality of image and field of view . The initial Corona missions suffered from mysterious border fogging and bright streaks which appeared irregularly on the returned film . Eventually , a team of scientists and engineers from the project and from academia ( among them Luis Alvarez , Sidney Beldner , Malvin Ruderman , and Sidney Drell ) determined that electrostatic discharges ( called corona discharge s ) caused by some of the components of the cameras were exposing the film . Corrective measures included better ground ing of the components , improved film rollers that did not generate static electricity , improved temperature controls , and a cleaner internal environment . Although improvements were made to reduce the corona , the final solution was to load the film canisters with a full load of film , feed the unexposed film through the camera onto the take - up reel with no exposure . This unexposed film was then processed and inspected for corona . If none was found or the corona observed was within acceptable levels , the canisters were certified for use and loaded with fresh film for a launch mission . The first satellites in the program orbited at altitudes above the surface of the Earth , although later missions orbited even lower at ) . Originally , Corona satellites were designed to spin along their main axis so that the satellite would remain stable . Cameras would take photographs only when pointed at the Earth . The Itek camera company , however , proposed to stabilize the satellite along all three axes — keeping the cameras permanently pointed at the earth . Beginning with the KH - 3 version of the satellite , a horizon camera took images of several key stars . A sensor used the satellite ' s side thruster rockets to align the rocket with these " index stars , " so that it was correctly aligned with the Earth and the cameras pointed in the right direction . Beginning in 1967 , two horizon cameras were used . This system was known as the Dual Improved Stellar Index Camera ( DISIC ) . Film was retrieved from orbit via a reentry capsule ( nicknamed " film bucket " ) , designed by General Electric , which separated from the satellite and fell to earth . After the fierce heat of reentry was over , the heat shield surrounding the vehicle was jettisoned at and parachutes deployed . The capsule was intended to be caught in mid - air by a passing airplane towing an airborne claw which would then winch it aboard , or it could land at sea . A salt plug in the base would dissolve after two days , allowing the capsule to sink if it was not picked up by the United States Navy . After Reuters reported on a reentry vehicle ' s accidental landing and discovery by Venezuelan farmers in mid - 1964 , capsules were no longer labeled " Secret " but offered a reward in eight languages for their return to the United States . Beginning with flight number 69 , a two - capsule system was employed . This also allowed the satellite to go into passive ( or " zombie " ) mode , shutting down for as many as 21 days before taking images again . Beginning in 1963 , another improvement was " Lifeboat " , a battery - powered system that allowed for ejection and recovery of the capsule in case power failed . The film was processed at Eastman Kodak ' s Hawkeye facility in Rochester , New York . Coronas were launched by a Thor - Agena rocket , which used a Thor first stage and an Agena booster ( which served as the second stage of the rocket lifting the Corona into orbit ) . With the implementation of the J - 1 camera system in 1963 , a Thorad rocket was used for the first stage , leading to large improvements in launch reliability . Later launches were made using the Thrust Augmented Thor ( TAT ) . Maneuvering rockets were also added to the satellite beginning in 1963 . These were different from the attitude stabilizing thrusters which had been incorporated from the beginning of the program . Corona orbited in very low orbits to enhance resolution of its camera system . But at perigee ( the lowest point in the orbit ) , Corona endured drag from the Earth ' s atmosphere . In time , this could cause its orbit to decay and force the satellite to re - enter the atmosphere prematurely . The new maneuvering rockets were designed to boost Corona into a higher orbit , and lengthen the mission time even if low perigees were used . For use during unexpected crises , the National Reconnaissance Office ( NRO ) kept a Corona in " R - 7 " status , meaning ready for launch in seven days . By summer 1965 NRO was able to maintain Corona for launch within one day . The procurement and maintenance of the Corona satellites was managed by the Central Intelligence Agency , which used cover arrangements lasting from April 1958 to 1969 to get access to the Palo Alto plant of the Hiller Helicopter Corporation for the production . At this facility , the rocket ' s second stage Agena , the cameras , film cassettes , and reentry capsule were assembled and tested before shipment to Vandenberg Air Force Base . In 1969 , assembly duties were relocated to the Lockheed facilities in Sunnyvale , California . ( The NRO was worried that , as Corona was phased out , skilled technicians worried about their jobs would quit the program — leaving Corona without staff . The move to Sunnyvale ensured that enough skilled staff would be available . ) The decisions regarding what to photograph were made by the Corona Target Program . Corona satellites were placed into near - polar orbits . This software , run by an on - board computer , was programmed to operate the cameras based on the intelligence targets to be imaged , the weather , the satellite ' s operational status , and what images the cameras had already captured . Ground control for Corona satellites was initially conduct from Stanford Industrial Park , an industrial park on Page Mill Road in Palo Alto , California . It was later moved to Sunnyvale Air Force Base near Sunnyvale , California . Corona launches with system types . Below is a list of Corona launches , as compiled by the United States Geological Survey . This table lists government ' s designation of each type of satellite ( C , C - prime , J - 1 , etc . ) , the resolution of the camera , and a description of the camera system . Discoverer . The first dozen or more Corona satellites and their launches were cloaked with disinformation as being part of a space technology development program called the " Discoverer " program . The first test launches for the " Corona / Discoverer " were carried out early in 1959 . The capsule of Discoverer 2 might have been recovered by the Soviets , after landing on Spitsbergen Island . The first Corona launch containing a camera was carried out in June 1959 with the cover name " Discoverer 4 " . This was a 750 kilogram satellite launched by a Thor - Agena rocket . The return capsule of the Discoverer 13 mission , which launched August 10 , 1960 , was successfully recovered the next day . This was the first time that any object had been recovered successfully from orbit . After the mission of Discoverer 14 , launched on August 18 , 1960 , its film bucket was successfully retrieved two days later by a C - 119 Flying Boxcar transport plane . This was the first successful return of photographic film from orbit . In comparison , Sputnik 5 was launched into orbit on August 19 , 1960 , one day after the launch of Discoverer 14 . Sputnik 5 was a biosatellite that took into orbit the two Soviet space dogs , Belka and Strelka , and then safely returned them to the Earth . At least two launches of " Discoverers " were used to test satellites for the Missile Defense Alarm System ( MIDAS ) , an early missile - launch - detection program that used infrared cameras to detect the heat signature of rockets launching to orbit . The " Corona " film bucket was later adapted for the KH - 7 GAMBIT satellite , which took higher resolution photos . The last launch under the " Discoverer " cover name was " Discoverer 38 " on February 26 , 1962 . Its bucket was successfully recovered in midair during the 65th orbit ( the 13th recovery of a bucket ; the ninth one in midair ) . Following this last use of the " Discoverer " name , the remaining launches of " Corona " satellites were entirely top secret . The last " Corona " launch was on May 25 , 1972 . The project was abandoned after a Soviet Navy submarine was detected waiting beneath a " Corona " mid - air retrieval zone in the Pacific Ocean . The best sequence of " Corona " missions was from 1966 to 1971 , when there were 32 consecutive successful missions , including film recoveries . An alternative program to the " Corona " program was named " SAMOS " . This program included several types of satellite which used a different photographic method . This involved capturing an image on photographic film , developing the film on board the satellite and then scanning the image electronically . The image was then transmitted via telemetry to ground stations . The Samos E - 1 and E - 2 satellite programs used this system , but they were not able to take very many pictures and then relay them to the ground stations each day . Two later versions of the Samos program , such as the E - 5 and the E - 6 , used the bucket - return approach , but neither of these programs carried out any successful missions . ELINT subsatellites . Nine of the KH - 4A and KH - 4B missions included ELINT subsatellites , which were launched into a higher orbit . Declassification . The " Corona " program was officially classified top secret until 1992 . Then , on February 22 , 1995 , the photos taken by the " Corona " satellites , and also by two contemporary programs ( " Argon " and KH - 6 " Lanyard " ) were declassified under an Executive Order signed by President Bill Clinton . The further review by photo experts of the " obsolete broad - area film - return systems other than " Corona " " mandated by President Clinton ' s order led to the declassification in 2002 of the photos from the KH - 7 and the KH - 9 low - resolution cameras . The declassified imagery has since been used by a team of scientists from the Australian National University to locate and explore ancient habitation sites , pottery factories , megalithic tombs , and Palaeolithic archaeological remains in northern Syria . Similarly , scientists at Harvard have used the imagery to identify prehistoric traveling routes in Mesopotamia . The " CORONA Digital Atlas of the Middle East Project " hosts a large number of KH - 4B imagery where users can view and download spatially corrected images . Popular culture . The 1963 thriller novel " Ice Station Zebra " and its 1968 film adaptation were inspired , in part , by news accounts from April 17 , 1959 , about a missing experimental Corona satellite capsule ( Discoverer II ) that inadvertently landed near Spitzbergen on April 13 . While Soviet agents may have recovered the vehicle , it is more likely that the capsule landed in water and sank . They are also mentioned in the video - game .