Apollo 15 Mission
Science Experiments - Metric and Panoramic Cameras
The Metric and Panoramic cameras provided systematic photography of the lunar surface.
The Scientific Instrument Module (SIM) on the Apollo 15 Service Module. Both the Metric and Panoramic cameras were located in the SIM bay. This photo was taken from the lunar module.
Apollo 15, 16, and 17 carried a set of cameras in the Scientific Instrument Module of the Service Module. These cameras were used to obtain high-resolution photographs of the lunar surface, for use both in studying the geology of the surface and for producing detailed topographic maps of the surface. These cameras included a Metric Camera, a Panoramic Camera, and a Stellar Mapping Camera. The Metric and Stellar Mapping Cameras were operated as a unit along with the Laser Altimeter. The Panoramic Camera was operated separately, but was often used at the same time as the Metric Camera. The film canisters used by these cameras were retrieved from the Service Module and stowed in the Command Module during a spacewalk by the Command Module pilot on the return trip to Earth.
The Metric Camera obtained pictures of the surface covering 165 kilometers on a side, with a horizontal resolution of 20 meters, based on a nominal spacecraft altitude of 110 kilometers. The Stellar Mapping Camera obtained photographs of star fields at the same time, which were used to establish the spacecraft's precise orientation, thus improving the accuracy of the resulting lunar maps. The Panoramic Camera obtained pictures of narrow strips, 20 kilometers wide in the direction of spacecraft motion and 320 kilometers long across the spacecraft's ground track. These pictures had extremely high resolution, showing features just 1 to 2 meters across. Photographs with both cameras were taken so that there was substantial overlap in the ground coverage of consecutive photos. This allowed the technique of stereo photography to be used to determine the heights of features shown in the photos. Under ideal conditions, the heights of these features could be determined to an accuracy of better than 10 meters. The results of this stereo photography were used in producing topographic maps.
During Apollo 15, the Metric Camera was used on 18 orbits and during the early hours of the return to Earth, obtaining 2240 usable photographs. The Panoramic Camera was used on 11 orbits and during the early hours of the return to Earth, obtaining 1529 usable photographs. This covered virtually all of the Moon visible in sunlight to the Apollo 15 crew.
Examples of Apollo 15 Metric Photography
This oblique photograph looks south across the Aristarchus plateau. There are two prominent impact craters in the photograph. On the left is Aristarchus, 40 kilometers in diameter, and on the right is Herodotus, 35 kilometers in diameter. In the center of the photograph, between the two craters, is a feature known as Cobra's Head. Beginning at Cobra's Head, the sinuous valley that snakes its way to the right is Schroter's Valley. Schroter's Valley, which is typically 8 to 10 kilometers wide and more than 150 kilometers long, most likely formed due to faulting when the Aristarchus Plateau was uplifted nearly 4 billion years ago. Within Schroter's Valley is a narrow, sinuous structure called a rille, which formed as a volcanic channel. Multispectral images obtained by the Clementine spacecraft have revealed the complex variations in rock composition in this area and have helped in interpreting this region's geologic history. (Apollo 15 Metric photograph AS15-2610.) This photograph shows part of the Apennine Mountains, which form part of the rim of the Imbrium Basin. In this region, the Apennines are up to 4 kilometers higher than the adjacent plains, which are called mare. The sinuous feature running roughly vertically through the center of the photograph is Hadley Rille. Like the rille in Schroter's Valley, Hadley Rille formed as a volcanic channel. The Apollo 15 mission landed near the center of this photograph, on the mare plains between Hadley Rille and the Apennines, and explored both features at close range. Samples returned by this mission indicate that the mare surface is basalt, with an age of about 3.3 billion years. The region shown is about 150 kilometers across. (Apollo 15 Metric photograph AS15-414.) This photograph shows Hadley Rille at ground level. In this region, the rille is 1.5 kilometers wide and 350 meters deep. (Apollo 15 photograph AS15-85-11451.) This oblique photograph looks north across the southern part of Mare Imbrium. The low sun angle and long shadows accentuate details of the surface structure. The surface in this area is mare basalt. A good example of a lava flow crosses the image from lower left to upper right. The prominent ridges running from upper left to lower right are wrinkle ridges, formed when the mare surface sagged under the weight of several kilometers of basalt. Similar wrinkle ridges are seen in other mare regions, including Mare Serenitatis and Mare Humorum. The prominent peak in the lower left is Mt. Lahire, which is 1.7 kilometers high. (Apollo 15 Metric photograph AS15-1555.) This oblique photo shows Tsiolkovsky crater, 180 kilometers across, on the Moon's farside. The very rugged nature of the ejecta blanket is evident on the right side of the photo. Within the ejecta, there are some relatively smooth patches. These may have formed from material that was melted by the heat generated by the Tsiolkovsky impact. (Apollo 15 Metric photograph AS15-757.) This overhead photograph shows details of the interior of Tsiolkovsky. Unlike many large craters, the floor of Tsiolkovsky is covered with mare material and is quite smooth. The crater itself is fairly circular, but the mare-covered region is distinctly noncircular. This is a rare example of mare material on the Moon's farside. The complex terracing and slump blocks on the interior side of the crater rim are typical of many large impact craters. The prominent central peak is also typical of large craters. (Apollo 15 Metric photograph AS15-1030.)
Photographs taken while looking down from great heights, such as from an airplane or an orbiting spacecraft, often have a two-dimensional quality to them, with little or no indication of how high the features shown in the image actually are. If a region is photographed from two different perspectives, the differences in appearance of the two photos can be used to determine the heights of features in the images. This is known as stereo photography and is similar to the process the human brain uses to merge the images from the left and right eyes into a single image that provides information about the distances to various objects.
The image shown here has been digitally processed to illustrate this stereo effect. The image should be viewed with special red-blue stereo glasses. The red lens goes over the left eye and the blue (or green) lens goes over the right eye.
Lambert Crater, 30 kilometers in diameter, is a typical example of a small, complex crater. In this image, one can see slumping and terracing of the inner rim of the crater, a central peak, and an ejecta blanket surrounding the crater rim. Lambert is about 2.4 kilometers deep and the rim is about 800 meters higher than the surrounding plains. The heights in this image are vertically exaggerated by a factor of 4.2. (Based on Apollo 15 Metric photographs AS15-260 and AS15-265. Stereo processing by Paul Schenk, Lunar and Planetary Institute. Stereo image © copyright Lunar and Planetary Institute, 1997.)
This photograph shows Dawes crater, 18 kilometers in diameter and about 2 kilometers deep, in southeastern Mare Serenitatis. Dawes is typical of moderate-sized lunar craters. Whereas small craters (less than about 15 kilometers in diameter) tend to have simple bowl-shaped forms, in larger craters, slumping of material off the interior of the crater rim helps to flatten the crater floor. Unlike larger craters, such as King or Tsiolkovsky, Dawes does not have terraces on the interior of the crater rim or a central peak. North is at the right side of this photograph. (Part of Apollo 15 Panoramic photograph AS15-9562.)
