Spacecraft currently studying Mars:

Mars Odyssey Orbiter

Mars Express

Mars Reconnaissance Orbiter

Mars Rover Spirit

Mars Rover Opportunity

Mars Lander Phoenix

This picture, taken on Thursday, Aug 14, shows a thin layer of frost on the ground around Phoenix. The Martian winter will reach Phoenix in a few weeks, so the temperatures are already dropping ....

One of the main goals of Phoenix is to bring portions of the Martian soil into a set of ovens to analyze it.