We really don't know what we're going to see. Beneath the Surface Also on Mars Polar Lander are two basketball-size probes that will detach from the main spacecraft about five minutes before entering the Martian atmosphere and then literally crash into the planet at about 400 miles per hour. That will allow part of the probes to penetrate three feet into the Martian soil in an effort to find frozen water there. One of the mysteries of Mars is where all its water has gone. Huge floods almost certainly carved the gigantic canyons on the Martian surface, but today the surface is dry.
Many planetary scientists believe the rest of the water is frozen beneath the surface.
But until you actually land there and find it and measure it, you can't say for sure. I think this mission will demonstrate. Polar Lander's microphone is also a first. Many believe the only sounds that might be heard in the thin Martian atmosphere will be the movement of the robot arm and the internal systems of the lander. There's a possibility, however slight, that the sound of dust or sand blowing against the lander also might be picked up.