Function: Global surviving and enduring military communications system.







Description: Milstar is a joint service satellite communications system that provides worldwide secure, jam resistant and low probability of detection nuclear-event resistant communications for all forces across the spectrum of conflict.



The multi-satellite constellation will link command authorities with a wide variety of resources, including ships, submarines, aircraft, land vehicles and manned-portable systems.



Milstar is the most advanced military communications satellite system to date and represents the future of the 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 (4,536 kilograms) and have a design life of 10 years.



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 (SMC) at Los Angeles AFB, CA, is responsible for development and acquisition of the Milstar space and mission control segments. The Electronics Systems Center (ESC) at Hanscom AFB, MA is responsible for the Air Force portion of the terminal segment development and acquisition. The 4th Space Operations Squadron at Schriever AFB, CO, is the front line organization providing real time satellite platform control and communications payload management.







History: The first Milstar satellite was launched Feb. 7, 1994 aboard a Titan IV expendable launch vehicle. The second was launched Nov. 5, 1995. Beginning with the fourth launch in 2000, the satellites will have greatly increased capacity because of an additional medium data rate payload. A total of three launches remain.







General Characteristics, Milistar Satellite Communications System





Primary Contractor:

Lockheed Martin Missiles and Space







Power Plant:

Solar panels generating 5,000 watts







Payload:

All satellites: Low data rate communications (voice, data, teletype and facsimile) at 75 bps to 2,400 bps



Medium data rate communications (voice, data, teletype, facsimile) at 4.8 kbps to 1.544 bps (Satellites 4 through 6 only)













Weight:

About 10,000 pounds (4,536 kilograms)







Orbit Altitude:

22,300 nautical miles (inclined geostationary orbit)







Launch Vehicle:

Titan IVB/Centaur upper stage







Inventory:

2







Unit Replacement Cost:

$800 million