In December 2014 Russia launched another Lotos S spy satellite. This is a six ton electronic surveillance satellite which an elliptical orbit that brings the satellite as low as 200 kilometers to earth. The first Lotos went up in 2009. Lotos is still classified as “experimental” and is part of the Russian effort to catch up with the United States in space-based ELINT (electronic reconnaissance, also called SIGINT for signals intelligence).
Meanwhile in June 2012 the U.S. launched its sixth (since 1995) Mentor ELINT satellite. These six ton birds deploy the largest antenna array (over 110 meters in diameter) ever used in a satellite. Details of how Mentor satellites operate is highly classified, but they are known to pick up a large number of electronic signals from ships, aircraft and ground stations, as well as other satellites. This data undergoes some processing on the Mentor satellite, is then encrypted and transmitted to American ground stations for further analysis. The American satellite ELINT program began in 1985 with a Space Shuttle putting two Magnum satellites (each 2.5 tons) into orbit.
Little is said about ELINT satellites because, more than photo satellites, these electronic listening birds can potentially pick up anything (radar, radio, whatever) that is broadcast from anywhere. This is an alarming possibility for producers and users of military electronics. Not knowing exactly what those enemy ELINT satellites are picking up is very disturbing. China, for example, has launched Cyber War type hacking attacks on American companies involved with collecting and analyzing Mentor satellite data. If the Chinese have reached the Mentor database, it has made Chinese electronics much less likely to encounter unpleasant surprises in wartime.