MILSTAR Satellite Communications System

M I L S T A R SATELLITE COMMUNICATIONS SYSTEM Milstar is a joint service satellite communications system that provides secure, jam resistant, worldwide communications to meet essential wartime requirements for high priority military users. The multi-satellite constellation will link command authorities with a wide variety of resources, including ships, submarines, aircraft and ground stations. Milstar is the most advanced military communications satellite system to date and represents the future of U.S. communications capability. The operational Milstar satellite constellation will consist of four satellites positioned around the Earth in geosynchronous orbits. Each mid-latitude satellite weighs approximately 10,000 pounds, and has a design life of 10 years. The first Milstar satellite was launched February 7, 1994 aboard a Titan IV expendable launch vehicle. The second was launched November 5, 1995. Beginning with the third launch in 1999, the satellites will have greatly increased capacity because of an additional medium data rate payload. A total of six launches are planned. Each Milstar satellite serves as a smart switchboard in space by directing traffic from terminal to terminal anywhere on the Earth. Since the satellite actually processes the communications signal and can link with other Milstar satellites through crosslinks, the requirement for ground controlled switching is significantly reduced. The satellite establishes, maintains, reconfigures and disassembles required communications circuits as directed by the users. Milstar terminals provide encrypted voice, data, teletype, or facsimile communications. A key goal of Milstar is to provide interoperable communications among the users of Army, Navy, and Air Force Milstar terminals. Geographically dispersed mobile and fixed control stations provide survivable and enduring operational command and control for the Milstar constellation. The Milstar system is composed of three segments: space (the satellites), terminal (the users), and mission control. Air Force Materiel Command?s Space and Missile Systems Center at Los Angeles AFB, California, is responsible for development and acquisition of the Milstar space and mission control segments. Next, the Electronics Systems Center at Hanscom AFB, Massachusetts, is responsible for the Air Force portion of the terminal segment development and acquisition. Additionally, the 4th Space Operations Squadron at Schriever AFB, Coloorado, is the front-line organization providing real-time satellite platform control and communications payload management. Milstar Specifications Weight: Approximately 10,000 lbs. Orbit Altitude: 22,250 nautical miles (inclined geostationary orbit) Power Plant: Solar panels generating 8,000 watts Payload: Low data rate communications (voice, data, teletype and facsimile) at 75 bps to 2,400 bps (All satellites) Medium data rate communications (voice, data, teletype, facsimile) at 4.8 Kbps to 1.544 Mbps (Satellites 3 through 6 only) Primary Contractor: Lockheed Martin Missiles and Space