|Possible landing ellipses for the Mars Phoenix lander. The Heimdall crater appears to have fewer boulders than other areas. The geomorphic mapping is overlaid on a shaded relief map based on data from the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. The red box indicates the location of an image RA4-CTX from the Context Camera on NASA's Mars Reconnaissance Orbiter. Image Credit: NASA/ JPL-Caltech/Washington Univ. St. Louis/JHU APL/Univ. of Arizona.