What is the purpose of the mission to Mars?

NASA decided to send a mission to the North Polar Region on Mars, because scientists say there is water in the form of ice under the soil near the poles. The Phoenix Lander has instruments onboard that can measure the physical and chemical characteristics of the ice. The mission won’t be able to tell whether anything is living in the water, but it can tell whether the water could support life. The mission has only one chance to land. It enters the atmosphere at more than 12, 000 miles per hour.