NASA/JPL/Malin Space Science Systems
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows raised-rimmed, circular features sometimes described as "boulder rings." These are located on the vast martian northern plains, and they are, basically, somewhat filled and somewhat buried meteor impact craters. The small, dark dots on these rings are boulders derived from the craters' ejecta and perhaps from erosion of the rock in which the craters formed. This image is located near 70.4°N, 310.4°W, and covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.
Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, California. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, California and Denver, Colorado.