U.S. Air Force Fact Sheet

Air Force Space Command-operated Defense Support Program (DSP) satellites are a key part of North America's early warning systems. In their 22,000 miles-plus geosynchronous orbits, DSP satellites help protect the United States and its allies by detecting missile launches, space launches and nuclear detonations.

DSP satellites use an infrared sensor to detect heat from missile and booster plumes against the earthís background. In 1995, technological advancements were made to ground processing systems, enhancing detection capability of smaller missiles to provide improved warning of attack by short-range missles against U.S. and allied forces overseas.

Numerous improvement projects have enabled DSP to provide accurate, reliable data in the face of evolving missile threats. On-station sensor reliability has provided uninterrupted service well past their design lifetime. Recent technological improvements in sensor design include above-the-horizon capability for full hemispheric coverage and improved resolution. Increased on-board signal-processing capability improves clutter rejection. Enhanced reliability and survivability improvements were also incorporated. In the 21st century, the Space-Based Infrared System (SBIRS) will replace DSP.

The program came to life with the first launch of a DSP satellite in the early 1970s. Since that time, DSP satellites have provided an uninterrupted space-based early warning capability. The original DSP satellite weighed 2,000 pounds and had 400 watts of power, 2,000 detectors and a design life of 1.25 years. Throughout the life of the program, the satellite has undergone numerous improvements to enhance reliability and capability. The weight grew to 5,250 pounds, the power to 1,275 watts, the number of detectors increased three-fold to 6,000 and the design life has been increased to a goal of five years.

The 21st Space Wing, with headquarters at Peterson Air Force Base, Colo., has units that operate DSP satellites and report warning information, via communications links, to the North American Aerospace Defense Command (NORAD) and U.S. Space Command early warning centers within Cheyenne Mountain, located near Colorado Springs, Colo. These centers immediately forward data to various agencies and areas of operations around the world. The Space and Missile Systems Centerís Space Based Infrared System Program office at Los Angeles AFB, Calif., is responsible for development and acquisition of the satellites.

Typically, DSP satellites are launched into geosynchronous orbit on a Titan IV booster and inertial upper stage combination. However, one DSP satellite was launched using the space shuttle on mission STS-44 (Nov. 24, 1991).

DSPís effectiveness was proven during Desert Storm, when DSP detected the launch of Iraqi Scud missiles and provided warning to civilian populations and coalition forces in Israel and Saudi Arabia.

General Characteristics
Primary mission: Strategic and tactical missile launch detection
Contractor team: Thompson Ramo Woolridge (TRW) and Aerojet Electronics Systems
Weight: 5,250 pounds (2,386 kilograms)
Orbit altitude: 22,000 miles (35,200 kilometers)
Power plant: Solar arrays generate 1,485 watts
Height: 32.8 feet (10 meters) on orbit; 28 feet (8.5 meters) at launch
Diameter: 22 feet (6.7 meters) on orbit; 13.7 feet (4.2 meters) at launch
Date Deployed: 1970
Latest Satellite Block: Sat 23
Unit Cost: $400 million
Inventory: Classified

Point of Contact
Air Force Space Command, Public Affairs Office; 150 Vandenburg St., Suite 1105; Peterson AFB, CO 80914-4500; 692-3731 or (719) 554-3731.

March 2003

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