Apollo 16 Mission
Science Experiments - Metric and Panoramic Cameras
Astronaut Thomas K. Mattingly II performs a spacewalk during the Apollo 16 trans-Earth coast to retrieve the film canisters from the metric and panoramic photography experiments in the Service Module. Mattingly is assisted by astronaut Charles M. Duke Jr., lunar module pilot.
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 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 16, the Metric Camera was used on 16 orbits and during the early hours of the return to Earth, obtaining 2491 usable photographs. The Panoramic Camera was used on eight orbits and during the early hours of the return to Earth, obtaining 1586 usable photographs. This covered virtually all of the Moon visible in sunlight to the Apollo 16 crew.
Examples of Apollo 16 Metric Photography
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 conceptually 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 images shown here have been digitally processed to illustrate this stereo effect. The images 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. These stereo images were processed by Paul Schenk, Lunar and Planetary Institute. (Stereo images © copyright Lunar and Planetary Institute, 1997.)
Example of Apollo 16 Panoramic Photography
This photograph was taken south of the crater Spencer Jones on the Moon's farside. It shows representative examples of small lunar craters. Such craters lack the terraced walls that typify large craters such as King Crater. The largest of the craters seen here, in the left-central part of the photograph, is about 15 kilometers across and has a flat floor. In many of the other craters, the floor of the crater is obscured by shadows. However, based on photographs of other small craters, it is known that craters smaller than about 15 kilometers in diameter on the Moon typically have curved, bowl-shaped floors, rather than the flat floors found in larger craters. North is to the right in this photograph. (Part of Apollo 16 panoramic photograph AS16-4136.)