This image from Phoenix's robotic arm camera shows how the Snow Queen feature appeared on June 15, 2008, the 21st Martian day, or sol, of the mission. Snow Queen is the informal name for a patch of bright-toned material underneath the lander, which scientists think could be Martian ice exposed by the lander's thrusters. Credit: NASA/JPL-Caltech/University of Arizona/Max Planck Institute
