Low Data Rate (LDR) Payload

The Northrop Grumman-built Milstar LDR payload receives uplink user signals on nine EHF receive antenna beams.  The uplink signals are demodulated and routed to destinations assigned by the onboard computers, which mark the world’s first “bandwidth on demand” satellite communications.  Data are also received via crosslinks from other Milstar satellites in the constellation.  Received user data may be routed either to onboard destinations, to one of five downlink antennas, or to the crosslinks for connections through other Milstar satellites that form a “closed ring” enabling secure, Milstar communications from point to point anywhere on Earth.
 
The SHF downlink subsystem modulates and transmits the signal through the downlink antennas.  A UHF subsystem provides interoperable UHF communications and a fleet broadcast channel.  Milstar supports communications to man-transportable terminals.  Click here to see a table of payload performance features.