What is the layer above ionosphere?

The layer above the ionosphere is the exosphere. It is the outermost layer of Earth's atmosphere, extending from about 600 kilometers (373 miles) above sea level to approximately 10,000 kilometers (6,200 miles). In the exosphere, atmospheric particles are extremely sparse, and it gradually transitions into outer space. This layer is where satellites orbit the Earth and where the atmosphere becomes so thin that it can no longer be considered a distinct layer.