The data will be obtained by measuring the intensities of gamma rays that emerge from the martian surface. These high-energy rays are created from the natural decay of radioactive elements or can be produced by the interaction of cosmic rays with the atmosphere and surface. By observing the number and energy of these gamma rays, it is possible to determine the chemical composition of the surface, element by element. The GRS also can measure the presence of water frozen in the polar caps and as ground ice if it is within 1 meter of the surface. The MOC will photograph the martian surface with the highest resolution ever accomplished by an orbiting civilian spacecraft.
Resolution is a measure of the smallest object that can be seen in an image.
To create these images, each of these camera systems uses the motion of the spacecraft in combination with what is called a line array of several thousand detectors. The low-resolution camera system will capture global views of the martian atmosphere and surface so that scientists may study the martian weather and related surface changes on a daily basis. Moderate-resolution images will monitor changes in the surface and atmosphere over hours, days, weeks, months, and years. The high-resolution camera system will be used selectively because of the high data volume required for each image. Click HERE for a line drawing of the MOC presented by Malin et al.