Abstract Real aperture, side looking X-band radars have been operated from the Soviet Cosmos-1500, -1602, -1766 and Ocean satellites since 1984. These radar systems observe a 475 km wide swath with 1–2 km horizontal spatial resolution. Wind velocities were inferred from sea surface radar scattering for speeds ranging from approximately 2 m/s to those of hurricane proportions. The wind speeds were within 10–20% of the measured in situ values, and the direction of the wind velocity inferred from the radar measurements agreed with in situ direction measurements within 20–50°. Various atmospheric mesoscale eddies and tropical cyclones were thus located, and their strengths were inferred from sea surface reflectivity measurements. Rain cells were observed over both land and sea with these spaceborne radars. Algorithms to retrieve rainfall rates from spaceborn radar measurements were also developed. Spaceborne radars have been used to monitor various marine hazards. For example, information derived from those radars was used to plan rescue operations of distressed ships trapped in sea ice. Icebergs have also been monitored. Because oil films reduce the sea surface roughness and thereby alter the radar reflectivity, oil spills were also mapped. Tsunamis produced by underwater earthquakes were also observed from space by the radars on the Cosmos-1500 series of satellites. The Cosmos-1500 satellite series have provided all weather radar imagery of the earth's surface to a user community in real time by means of a 137.4 MHz Automatic Picture Transmission (APT) channel. This feature enabled the radar information to be used in direct support of Soviet polar maritime activities.