1. Communications satellites are used to relay signals between different parts of the world, such as television, telephone, and internet signals. They are placed in geostationary orbit, which means that they stay in the same position relative to the Earth, allowing for continuous communication.

2. Earth observation satellites are used to collect information about the Earth's surface, such as weather patterns, land use, and natural resources. They are placed in a variety of orbits, depending on the type of data that they are collecting.