U.S. Air Force Fact Sheet

MILSTAR SATELLITE COMMUNICATIONS SYSTEM

Mission

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 links command authorities with a

wide variety of resources, including ships,

submarines, aircraft and ground stations.

Features

Milstar is the most advanced military

communications satellite system to date. The

operational Milstar satellite constellation

consists of five satellites positioned around

the Earth in geosynchronous orbits. Each

mid-latitude satellite weighs approximately

10,000 pounds (4,536 kilograms) and has 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.

Background

The first Milstar satellite was launched Feb. 7, 1994 aboard a Titan IV expendable launch

vehicle. The second was launched Nov. 5, 1995. The third launch on April 30, 1999, placed the

satellite in a non-usable orbit. The fourth through six satellites have a greatly increased capacity

because of an additional medium data rate payload and were launched on Feb. 27, 2001, Jan.

15, 2002, and April 8, 2003

The Milstar system is composed of three segments: space (the satellites), terminal (the users)

and mission control. Air Force Space Command's Space and Missile Systems Center at Los

Angeles Air Force Base, Calif., developed the Milstar space and mission control segments. The

Electronics Systems Center at Hanscom AFB, Mass., developed the Air Force portion of the

terminal segment. The 4th Space Operations Squadron at Schriever AFB, Colo., is the front-line

organization providing real-time satellite platform control and communications payload

management.

General Characteristics

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Primary function: Global military communications system

Primary contractor: Lockheed Martin Missiles and Space

Power plant: Solar panels generating 8,000 watts

Weight: About 10,000 pounds (4,536 kilograms)

Orbit altitude: 22,250 nautical miles (geosynchronous orbit)

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 4 through 6 only)

Launch vehicle: Titan IVB/Centaur upper stage

Inventory: 5

Unit Cost: $800 million

Point of Contact

Air Force Space Command, Public Affairs Office; 150 Vandenberg St., Suite 1105; Peterson

AFB, CO 80914-4500; DSN 692-3731 or 719-554-3731.

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