When the MRO flew high above Gale Crater on Jan. 2, Curiosity was spotted (the white feature, far right) with wheel tracks rolling over the undulating landscape from "Bradbury Landing," Curiosity's landing site (the dark feature, far left) on Aug. 5, 2012.
Apart from keeping tabs on Curiosity's progress, the HiRISE team can understand some of the characteristics of the Martian surface that Curiosity is rolling over. In some locations, the dark tracks are highly visible, in others, they're not. "The tracks are not seen where the rover has recently driven over the lighter-toned surface, which may be more indurated (hardened) than the darker soil," writes Alfred McEwen, lead HiRISE scientist and professor of planetary geology at the Arizona State University.
For me, whenever I see HiRISE observations of our robotic emissaries on the surface of Mars, I'm still blown away that we have robots looking out for other robots on another planet. If that's not awesome, I'm not quite sure what is.
Image credit: NASA/JPL/University of Arizona