The Mars Science Laboratory is a special spacecraft that was sent to Mars to explore the surface of the planet and collect information about the environment. It is about the size of a car and has various special sensors that help it study things like the atmosphere of Mars, the soil, and any rocks that it passes. The spacecraft also carries a rover called Curiosity which can drive on the surface of Mars and collect even more information about the planet. It is helping scientists learn more about Mars and its potential to host life!