TDRs satellite, 1980s.
© National Aeronautics & Space Administration / Science & Society
This picture shows the first complete satellite of the Tracking and Data Relay Satellite System (TDRs). TDRs were geostationary satellites developed by the United States and used to receive data from low-flying satellites before then re-broadcasting the data to the ground. These satellites were launched throughout the 1980s and 1990s using Space Shuttles.