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ER-2s over Golden Gate Bridge

ER-2 Program History

The NASA High Altitude Aircraft Program began operation in April 1971 with the loan of two Lockheed U-2C aircraft from the U.S. Air Force to the National Aeronautics and Space Administration. Prior to delivery to Ames Research Center, California, the aircraft received extensive maintenance and repainting at Palmdale, California by Lockheed Aircraft Company. With the arrival of the U-2C's at Ames Research Center, and after several familiarization and equipment functional check flights, the Earth Resources Aircraft Program began data acquisition flights on 31 August 1971 with a flight over the San Francisco Bay/Sacramento, California area.

The initial purpose of the aircraft project was to acquire small scale, low resolution, multispectral photography over selected representative ecosystems to simulate the Return Beam Vidicon (RBV) data system which would be aboard the future Earth Resources Technology Satellite (ERTS;Landsat1). Four 70 mm framing cameras were mounted vertically in the equipment bay to simultaneously image the same ground area. Equipped with 1-3/4 inch (44.5 mm) focal length lenses, the first three cameras were flown with black and white emulsion film, spectrally filtered to image the green, red and near infrared portions of the electro-magnetic spectrum, with the fourth camera loaded with color infrared film.

Initially, five test sites were designated to be flown on an 18-day repetitive basis; the orbit cycle of the future satellite. The Feather River Basin in northern California was chosen as representative of western U.S. forests, mountainous, and agricultural areas; the San Francisco Bay region and Los Angeles Basin as representative of urbanized areas; the Phoenix/Tucson region of Arizona, characteristic of arid regions, and the Chesapeake Bay region, representing wetland ecosystems.

In early 1972, as flights continued over the initial five test sites, a reconnaissance system previously flown aboard the aircraft was incorporated into the project's inventory; the A-1 configuration, a single 24-inch focal length, 9 x 18 inch film format camera with an accompanying tri-metragon array of 6-inch focal length cameras. Additionally, a NASA Goddard Space Flight Center-built multispectral scanner was integrated into the aircraft, providing a full ERTS simulation capability to the aircraft program. Concurrent integration of a Wild-Heerbrug RC-10 metric camera into the standard satellite simulation package resulted in a five instrument system which would continue to be flown for most multi-stage sampling flights.

With the delay in the launch of the ERTS from January to July, 1972, and with numerous investigators on contract to work with the satellite data, a second mode of data collection was instituted in order to provide those investigators with site-critical data requirements for the spring and summer period. Pre-ERTS Investigator Support routes were developed which provided repetitive satellite simulation data over numerous individual test sites.

The summer of 1972 brought the inception of a new project, the Arizona Land Use Experiment. A cooperative program between the state of Arizona, the U.S. Geological Survey, and NASA resulted in the acquisition of cloud-free black and white panchromatic metric photography in addition to the standard ERTS simulation multispectral photography. This photography was utilized by the Geological Survey to produce 7.5 minute, 1:24,000 scale orthophoto quadrangle sheets. Using new orthophoto compilation techniques, full quadrangle compilation could be accomplished from a single stereo model, eliminating the extra step of photographically mosaicing separate models into quad sheet representations. This was the first demonstration of the use of high altitude aircraft data for quadrangle map production over a large area.

With the launch of ERTS-1, the aircraft project began flying specific test sites for investigators, often simultaneously with the satellite overpass. Most flights were flown with the Vinten/RC-10 system providing small-scale satellite simulation data along with larger scale, larger format data.

Expanding the scope of the project, in support of crew training for Skylab, flights were flown over the eastern and western regions of the U.S. for use in the Skylab simulator. Additionally, in 1972 the project conducted its first disaster assessment missions, with data collection flights over hurricane and wild-fire damaged areas.

Early 1973 brought the first data flights with the A-3 camera configuration. The A-3 was derived from the A-2, a tri-metragon array of 24-inch focal length, 9 x 18 inch film format cameras. Mounted vertically, the A-3 provided a multi-emulsion or a multispectral photographic capability.

This camera system was employed over Roseville, California following a munitions train explosion in the railroad classification yard and over a number of wilderness fires in support of the California Department of Forestry. Throughout 1973 there was extensive flying activity in support of ERTS investigations on both the east and west coasts as well as continued flying for the Arizona Land Use Experiment.

During late 1973 the Stratospheric Air Sampler was integrated into the U-2 followed in early 1974 by the Aerosol Particulate Sampler. These two systems served as the core instrumentation for flights to the north and south in what would become the first systematic development of a global stratospheric model. Eielson Air Force Base, near Fairbanks, Alaska, served as the deployment base for flights over the northern polar region with six flights accomplished during this first deployment. Polar navigation was accomplished by sextant attachment to celestial objects. While deployed to Alaska, high altitude photographic data was acquired over a number of Arctic and sub-Arctic ecosystems in support of ERTS investigations.

The summer Alaskan deployment was followed in October by a deployment to Hickham Air Force Base, Hawaii with stratospheric sampling southward to near equatorial latitudes. These two deployments and local sampling flights provided the first comprehensive sampling of stratospheric constituents in the northern hemisphere and aided in the development of latitudinal distribution models of the upper atmosphere.

Late 1974 brought the Itek Optical Bar to the aircraft program. Similar to the Lunar Mapper carried aboard the Apollo orbiter, the Optical Bar is a 120 degree field of view, 24-inch focal length panoramic camera. This was followed in early 1975 with the HRB Singer thermal scanner and Goddard Space Flight Center's Heat Capacity Mapper. During the year, air sampling deployments were again conducted from Eielson and Hickham Air Force Bases and from Wallops, Virginia.

In 1976, the stratospheric sampling operating bases were expanded to include Howard Air Force Base, Panama and Loring Air Force Base, Maine, giving even greater sampling depth to the existing deployment sites. During these years of sensor development and expansion, terrestrial aerial photographic data acquisition continued in support of LandSat and other investigations. A new system was proposed and integrated aboard the U-2 aircraft; Aether Drift. This system was a pair of upward-looking microwave antennae and associated processing and recording systems. Flying at altitude, well above terrestrial sources of radiation, and observing the background radiation differentials from the two antennae, the system was designed to support or reject the validity of catastrophic evolutionary (big-bang) theories. Numerous flights were flown both in 1977 and 1978 in support of this astrophysics experiment.

The inception and commencement of the Alaska High Altitude Photography Program occurred in 1978. Faced with the administration, mapping, surveying and conveyance of federal lands to the State and native corporations, a consortium of Federal and State agencies requested NASA's assistance in acquiring high altitude black and white and color infrared photography of the entire state. Over the next eight years, flights were conducted resulting in 95% of Alaska photographed with color infrared and black and white films with less than 10% cloud cover.

During 1979, the Daedalus Multispectral Scanner was integrated onto the aircraft providing the first digitally recorded multispectral scanner operated as aircraft project equipment. The Aether Drift system was successfully deployed to Lima, Peru for a series of flights in the southern hemisphere.

Stratospheric sampling continued in 1979 and 1980 from Ames, Alaska, and Panama. Photographic data acquisition began in support of the National Wetlands Inventory over the Prairie Potholes region of the mid-west, an important migratory bird breeding habitat.

Acquisition of a replacement for the aging U-2C aircraft was accomplished during 1981 with the delivery of a new ER-2 from Lockheed. This procurement was completed concurrent with the first production of TR-l aircraft by the U.S. Air Force.

As a precursor to a satellite severe thunderstorms detection and warning system, a suite of sensors was developed and installed on board the U-2C and ER-2 aircraft. Multiple flights were flown over a variety of weather systems to develop response characteristics of the systems.

A cooperative program between NASA, the U.S. Forest Service and eastern seaboard states was initiated in 1983 to detect and monitor Gypsy Moth infestations in the northeast region of the country. Utilizing the Optical Bar panoramic camera and, subsequent to its replacement, the Iris II panoramic camera, high resolution color infrared photography has been acquired annually to detect and evaluated the severity of infestation from New York to North Carolina. In order to successfully discriminate the severity of defoliation attributable to the gypsy moth, the data must be acquired within a narrow biological window dictated by latitude, elevation, and annual weather conditions. Acceptable timing is within one week of an optimal date.

The first deployment of the aircraft outside of the western hemisphere occurred in 1985 to Alconbury, England for a remote sensing campaign. This was followed in early 1987 with a deployment to Darwin, Australia for stratospheric sampling. 1987 also brought the first engineering/integration test flights of NASA-JPL's Airborne Visible and Infrared Imaging Spectrometer (AVIRIS). AVIRIS is a 224 band multispectral scanner, a precursor to future satellite systems.

In the fall of 1987 the aircraft returned to South America for sub-polar stratospheric sampling over the Antarctic continent, operating from Punta Arenas, Chile. Significantly, these flights confirmed the existence of an "ozone hole" over the southern polar region and rejected theoretical polar symmetry of upper atmospheric models.

In 1988, with wilderness fires burning over much of the greater Yellowstone area, the ER-2's high altitude, long range capabilities were called upon to assist in delineating and mapping the multiple fire complexes. Operating from Moffett Field, the aircraft flew over the greater Yellowstone area, relaying thermal and near infrared imagery data in real time to a ground receiving station in West Yellowstone, Wyoming. This data provided the first comprehensive view of the multiple fire fronts, their activities, and their interrelationships.

In January 1989 the aircraft deployed to Stavanger, Norway in support of the Airborne Arctic Stratospheric Expedition. Multiple flights were conducted over northern Europe in support of the stratospheric sampling program.

In April 1989, the last U-2C model flights were conducted and the aircraft was removed from service.

An ER-2 deployment in June 1991 to Alconbury, England, brought the AVIRIS, Thematic Mapper Simulator, and RC-10 Camera to Europe. Multiple flights were flown over Iceland, Wales, England, France, Italy, Spain, Austria, Germany, and Netherlands. With the return of the aircraft to the United States, it then conducted stratospheric sampling from Eielson, AFB, Alaska to the North Pole.

The U-2C aircraft and its successor, the ER-2, have proven themselves to be a highly flexible and unique remote sensing and sampling platform. With its ability to fly at high altitudes for extended periods with multiple payloads it has proven to be a highly cost effective, versatile platform for comprehensive sampling, observation, and mapping.