Edward L Waltz
[Edward L. Waltz is a systems engineer with the Aerospace Systems Division of Bendix Corporation. He has been responsible for the development of ERTS MSS processing systems for the NASA Goddard Space Flight Center and the Brazilian National Space Agency.]
The recent disclosure that the camera of a U.S. satellite has photographed a tiny dot on Mt. Ararat which may be Noah’s Ark has caused wide interest among groups hopeful of finding the ancient artifact. (Detroit Free Press, February 23, 1974; Moody Monthly, April 1974.) Senator Frank E. Moss (D. Utah) stated that Dr. John Montgomery has possibly identified the Ark remains in an Earth Resources Technology Satellite (ERTS) photograph. In this article, we shall discuss how these photographs are made and the possibility of detecting the Ark in them.
The first ERTS spacecraft was launched on July 23, 1972 and a second spacecraft is being readied for launch early in 1975. Photographs of the earth’s surface are made with a multispectral scanner (MSS) on board the satellite. The MSS is an electromechanical line scanning device which collects four separate images of a 100 nautical mile wide swath along the satellite ground track. The four images are radiometric measurements of four spectral bandwidths: 0.5-0.6, 0.6-0.7, 0.7-0.8, and 0.8-1.1 micrometers. The instrument collects a 100 mile west to east “scan line” in 0.073 second by scanning a flat mirror perpendicular to the satellite ground track. As the spacecraft moves from north to south, contiguous scan lines build up a two dimensional radiometric image. The image is composed of a matrix of measurement “samples” which are represented by a series of coded numbers which are transmitted to receiving stations in the United States.
Twice every eighteen days, the ERTS orbit passes over Ararat such that the imagery includes the mountain. Since Turkey is not within range of the ERTS receiving stations located in the continental U.S., the Ararat imagery must be recorded by an on-board tape recorder
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and played back while over the U.S. Such recording-playback sequences were commanded on the following six days during the lifetime for the ERTS-1 on-board tape recorder: 11–22-72, 2–19-73, 2–20-73, 3–9-73, 7–13-73, and 7–14-73. Tape recorder degradation which began in late 1973 prohibited the collection of any further imagery over Ararat.
The ability of the Ark to be detected by the MSS is a function of several factors: (1) contrast of the Ark material against the background, (2) size of the Ark or exposed portions and (3) position of the Ark with respect to the direction of the satellite sensor scans. If exposed, the contrast of Ark remains should be quite good assuming high absorbtion of solar energy by a wooden, pitched material (Genesis 6:14) against a highly reflective snow or ice background. The Ark dimensions (approximately 135 x 25 meters from the top view1 ) of Genesis 6:15 are at the very limits of the 50–90 meter ground resolution of ERTS. Under optimal conditions with the Ark fully exposed, it could appear as a single dark dot in the image.
East West-to-East scan of the MSS image covers an 80 meter wide path which is divided into 3200 individual measurements, each 60 meters long: the total image is then reconstructed as a matrix of these 60 x 80 meter rectangular “picture elements.” Each picture element is represented by a set of four numbers: the radiance measurements of the area in each spectral band. The real question of Ark detectability then lies in whether the Ark remains absorb sufficient energy to make a detectable change in the data for the two or three measurements which are made on it. Such changes could appear as a dark dot in the film imagery. Although it is not likely that the shape of the Ark could be recognized, it may be possible to detect the Ark and other objects of similar size without distinguishing between them. Ocean piers of slightly smaller dimensions have been successfully measured in ERTS Imagery.2 If the Ark has been broken and the materials distributed over a larger area of the ice fields, a larger signal could be detected, depending upon the density and depth of the materials in the ice. Therefore, the numerous scattered dark spots seen in the mountain’s glaciers may represent candidates for further investigation, but are not uniquely distinguishable as the Ark.
The only other civilian opportunity to acquire higher resolution imagery of Ararat occurred during the manned SKYLAB missions. The Department of Interior EROS data center reports, however, that
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The image of Ararat above was acquired by the ERTS multispectral scanner on November 22, 1972. This was the first ER TS image of Ararat and clearly showed the two Ararat peaks, the Ahora Gorge, and glacial structures. Notice the very low snowline and the large shadowed areas due to the low November sun angle. The image to the right is a July 13, 1973 view with the receded summer snow line. The numerous dark dots on the mountain may represent candidates for future Ark expeditions but are not uniquely recognizable as the artifact.
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This elevation map shows the major features of the Ararat topography.
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no SKYLAB photography was collected over Ararat. Since very high resolution data acquired by U.S. Air Force reconnaissance satellites is classified and currently unavailable to the public, it is unlikely that greater resolution imagery will be available until the launch of the next generation of Earth Resources Satellites. The launch of these civilian Earth Observation Satellites (EOS) is scheduled to occur late in this decade. It is unlikely that the Strategic Arms Limitation Treaties (SALT) will result in the public release of reconnaissance photography, but if this is accomplished it would be feasible to obtain photographic data of sufficient resolution to easily distinguish the Ark if exposed. At the present time, however, the ERTS photographs provide valuable data which is of sufficient resolution to map the ice fields and identify large anomalies which deserve more detailed examination in future expeditions.