Icy satellites are a group of natural satellites or moons in the outer solar system that are primarily composed of ice, such as water ice, ammonia ice, and methane ice. These icy satellites are found orbiting gas giants like Jupiter, Saturn, Uranus, and Neptune. Research on icy satellites involves studying their surface composition, geology, and internal structure to understand their formation and evolution. Scientists are also interested in studying the potential for subsurface oceans and the possibility of life on these moons. Some of the most well-known icy satellites include Europa and Ganymede (orbiting Jupiter), Enceladus and Titan (orbiting Saturn), and Triton (orbiting Neptune). This research area is significant in the field of planetary science and astrobiology.