Overview: Phoenix Mars Lander - NASA's latest robot has already found frozen water and is looking for more signs that the Red Planet could support life. Brain Trauma - Even so-called "mild" head injuries turn out to be anything but. Mammoth Mystery - A pair of mammoth skeletons is found locked together by their tusks. What happened? Profile: Judah Folkman - Once scorned for his ideas about how cancer grows, the late Judah Folkman is now hailed as a visionary.