CloudSat uses a type of sensor called a radar. CloudSat's radar sends radio waves inside clouds. It then measures how these waves are reflected back to the satellites. This helps us to better understand the cloud’s structure. Scientists use data from NASA’s CloudSat and CALIPSO satellites together to make 3D models of how clouds and tiny particles in the air (called aerosols) form, evolve and affect weather, climate, and air quality. CloudSat was developed with the Canadian Space Agency.