The chart source dataset is extracted from Space-Track.org, a website maintained by the 18th Space Defense Squadron of the United States Space Force. The original data includes information on more than 50,000 space objects tracked over time, including their launch date and decay date (if they have reentered the Earth’s atmosphere). In this chart, low Earth orbit is defined by a periapsis altitude below 2,000 kilometers; medium Earth orbit between 2,000 and 35,586 kilometers; geostationary orbit between 35,586 and 35,986 kilometers; high Earth orbit above 35,986 kilometers.
Edouard Mathieu and Max Roser (2022) – “Space Exploration and Satellites”. Published online at OurWorldInData.org. Retrieved from: ‘https://ourworldindata.org/space-exploration-satellites’ [Online Resource]