Set to launch next month, NASA's Phoenix Mars Lander will probe the frozen soil on the planet's northern plains for clues of past life and the possibility of future life. The stationary vehicle will test Mars's frozen ice layer, which NASA expects to lie a few inches below the surface, to determine whether primitive microbes could live there. NASA announced this week that Phoenix (shown here being lowered into a vacuum chamber to simulate the rigors of spaceflight) is being prepared for a three-week launch window in August.