With a launch due in August 2007, the mission planners for the Phoenix probe to Mars are still struggling to identify a safe landing site near to the northern polar region. The already orbiting Mars Odyssey has been using a thermal camera to look down at night and identify hot spots from cooling rocks on the surface. Unfortunately, the prime landing area proved to harbour a minefields worth of rocks that would make a landing there extremely perilous. The Mars Reconnaissance Orbiter is also getting into the act, using its High Resolution Science Imaging Experiment (HiRISE) camera to take daytime shots. The primary mission of Phoenix is the search for water, hence the importance (and restrictions) of finding a polar landing site. Once down, the probe will use a robotic tool to dig up to 3 feet down into the Martian surface. Space.com has the full story of the ongoing effort to find a safe landing spot.