The first generation of U.S. photo intelligence satellites collected more than 860,000 images of the Earth’s surface between 1960 and 1972. The classified military satellite systems code-named CORONA, ARGON, and LANYARD acquired photographic images from space and returned the film to Earth for processing and analysis.
The images were originally used for reconnaissance and to produce maps for U.S. ... intelligence agencies. In 1992, an Environmental Task Force evaluated the application of early satellite data for environmental studies. Since the CORONA, ARGON, and LANYARD data were no longer critical to national security and could be of historical value for global change research, the images were declassified by Executive Order 12951 in 1995.
The first successful CORONA mission was launched from Vandenberg Air Force Base in 1960. The satellite acquired photographs with a telescopic camera system and loaded the exposed film into recovery capsules. The capsules or buckets were de-orbited and retrieved by aircraft while the capsules parachuted to earth. The exposed film was developed and the images were analyzed for a range of military applications.
The intelligence community used Keyhole (KH) designators to describe system characteristics and accomplishments. The CORONA systems were designated KH-1, KH-2, KH-3, KH-4, KH-4A, and KH-4B. The ARGON systems used the designator KH-5 and the LANYARD systems used KH-6. Mission numbers were a means for indexing the imagery and associated collateral data.
A variety of camera systems were used with the satellites. Early systems (KH-1, KH-2, KH-3, and KH-6) carried a single panoramic camera or a single frame camera (KH-5). The later systems (KH-4, KH-4A, and KH-4B) carried two panoramic cameras with a separation angle of 30° with one camera looking forward and the other looking aft.
The original film and technical mission-related documents are maintained by the National Archives and Records Administration (NARA). Duplicate film sources held in the USGS EROS Center archive are used to produce digital copies of the imagery.
Mathematical calculations based on camera operation and satellite path were used to approximate image coordinates. Since the accuracy of the coordinates varies according to the precision of information used for the derivation, users should inspect the preview image to verify that the area of interest is contained in the selected frame. Users should also note that the images have not been georeferenced.
The CORONA Image collection was driven, in part, by the need to
confirm purported developments in then-Soviet strategic missile
capabilities. The images also were used to produce maps and charts for
the Department of Defense and for other Federal Government mapping
programs. The CORONA system provided a cost effective method to map the earth
from space with stereo-optical ... images. CORONA demonstrated that the ability
to adapt rapidly to a changing world is critical to the success of U.S.
intelligence. This need to adapt grows even more acute as the pace of
technological advancement increases. Data provided by CORONA offers beneficial
information for environmentalists, scientists, scholars, and historians.
In addition to the images, documents and reports (collateral
information) are available, pertaining to frame ephemeris data, orbital
ephemeris data, and mission performance. Document availability varies by
mission; documentation was not produced for unsuccessful missions. Corner
coordinate data is a critical component of the index information. Accuracy in
locating corner coordinates varies according to how coordinates were derived
and according to the accuracy of information used for the derivation. As a
general rule, metadata corner points have errors less than 10 miles from their
actual ground positions for the CORONA and LANYARD systems, and less than 50
miles for the ARGON system. After a search of the metadata, the user should
inspect the browse image and its immediate neighbors in the image series for
the point of interest before placing an order for photography. For example,
each CORONA image is about 10 miles wide and looking at three consecutive
images in a series will compensate for 10 mile errors in cornerpoint
locations. The Appendix Guidance on Metadata Accuracy gives insights into the
accuracy of corner coordinate data used within the imagery index, and will aid
the reader in using the index to select imagery frames of interest. Also, the
use of browse imagery allows the user to review a reduced resolution image to
determine whether or not a specific site is contained in the selected frame.