The rock, informally named "Headless," that Phoenix 's robotic arm will try to move. Headless is about 19 centimeters (7 inches) long, 10 centimeters (4 inches) wide, extends 2 to 3 centimetes (about 1 inch) above the surface. This image, actually a mosaic of images taken by the lander's Surface Stereo Imager on Aug. 25 and 26, show the workspace reachable with the robotic arm. Credit: the workspace reachable with the robotic arm.
