Orion (satellite)

Orion, also known as Mentor or Advanced Orion, is a class of United States spy satellites that collect signals intelligence (SIGINT) from space. Operated by the National Reconnaissance Office (NRO) and developed with input from the Central Intelligence Agency (CIA), five have been launched from Cape Canaveral on Titan IV and Delta IV rockets since 1995. These satellites collect radio emissions (SIGINT) from geostationary orbits and act as replacements for the older constellation of Magnum satellites. Observers estimate the satellites weigh close to 5,200 kg and have very large (estimated 100 m diameter) radio reflecting dishes. NRO L-32, which is seen as the fifth satellite in the series, is according to NRO director Bruce Carlson "(...) the largest satellite in the world". It is believed that this refers to the diameter of the main antenna, which might be well in excess of 100 m. The mission and capabilities of these satellites are highly classified. Earlier satellites with similar missions, the Rhyolite/Aquacade series, were built by TRW; it is not known who made the Orion satellites.