Milstar provides the President, Secretary of Defense and the U.S. Armed Forces with assured, survivable satellite communications with low probability of interception and detection. Designed to overcome enemy jamming and nuclear effects, Milstar is the most robust and reliable SATCOM system currently employed by the Department of Defense.


The objective of the Milstar program was to create a survivable, secure, nuclear-survivable, space-based communication system, which was considered a top national priority during the Reagan Administration. Milstar was designed to perform all communication processing and network routing onboard, thus eliminating the need for vulnerable land-based relay stations and reducing the chances of communications being intercepted on the ground.


Milstar is known as "the FedEx of communications systems--when it absolutely, positively has to be there, Milstar is the system." There are five operational Milstar satellites. The first two satellites (Milstar I) carry a low data rate payload. The LDR payload can transmit 75 to 2,400 bps of data over 192 channels in the extremely high frequency (EHF) range. Encryption technology and satellite-to-satellite crosslinks provide secure communications, data exchange and global coverage. The other three satellites (Milstar II) carry both LDR and medium data rate payloads. The MDR payload can transmit 4,800 bps to 1.544 Mbps of data over 32 channels. The higher data rates provide the user the ability to transmit large amounts of data in a short period of time. These five satellites plus one Advanced EHF satellite (the follow-on satellite system launched in August 2010) will provide continuous 24-hour LDR and MDR coverage to the warfighter between 65 degrees north and 65 degrees south latitude.

A key feature of the Milstar system is the use of interoperable terminals by the warfighters of the U.S. Armed Forces. For example, sea-based terminals can be used to upload data onto cruise missiles carried aboard submarines and guided missile destroyers in real time. Land-based terminals provide communications and data exchange for the mobile, ground-based warfighter. The Air Force has the primary responsibility for managing the $6 billion Milstar program, which was acquired and is sustained by the MILSATCOM Systems Directorate.

Primary command and control of the Milstar constellation is accomplished through a highly survivable mission control segment with both fixed and mobile control stations. On October 19, 2005, the Command and Control Segment, which provided a secondary method of command and control, was replaced with a more modern system, the Command and Control System-Consolidated (CCS-C). This integrated system provides backup command and control through S-band links for both Milstar and the Advanced EHF satellite systems.

General Characteristics

Primary Function:
Survivable and protected communications
Primary Contractor: Lockheed Martin
Payload: LDR, MDR, & UHF
Antennas: LDR: Earth Coverage (uplink & downlink), Agile Beams (5 uplink, 1 downlink), Spot Beams (2 narrow, 1 wide), MDR: 2 Nulling, 6 Distributed User Coverage Area Capability: LDR: 75 bps - 2.4 kps / MDR: 4.8 kps 1.544 Mbps