This view of a Martian rock slab called "Old Soaker," which has a network of cracks that may have originated in drying mud, comes from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover.
The location is within an exposure of Murray formation mudstone on lower Mount Sharp inside Gale Crater. Mud cracks would be evidence of a time more than 3 billion years ago when dry intervals interrupted wetter periods that supported lakes in the area. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Old Soaker.
Several images from Mastcam's left-eye camera are combined into this mosaic view. They were taken on Dec. 20, 2016, during the 1,555th Martian day, or sol, of Curiosity's work on Mars.
The Old Soaker slab is about 4 feet (1.2 meters) long. Figure 1 includes a scale bar of 30 centimeters (12 inches). The scene is presented with a color adjustment that approximates white balancing, to resemble how the rocks and sand would appear under daytime lighting conditions on Earth.