Sfera (satellite series)

The Sfera series was a Soviet/Russian program of geodetic satellites launched between 1968 and 1990. These satellites were designed primarily for high-precision mapping of the Earth's surface. Sfera satellites utilized optical tracking methods from ground stations to determine their orbits with a high degree of accuracy. This precise orbital data, combined with the satellite's position relative to known ground control points, enabled the creation of improved topographic maps and the refinement of geodetic networks across the globe. The Sfera program contributed significantly to understanding the Earth's shape and gravity field. Data collected was also used for geophysical research and other scientific applications. The satellites were relatively simple in design compared to later, more sophisticated Earth observation platforms. They lacked active sensors and relied entirely on passive observation and tracking. The Sfera program's legacy lies in its contribution to improving the accuracy of global geodetic measurements and topographic mapping during the Cold War era.