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 earth's background. In 1995,
a new means of processing DSP data called Attack and Launch Early Reporting
to Theater (ALERT) was brought on line. This capability provides improved
warning of attack by short-range missiles against U.S. and allied forces
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 include enhanced sensor
resolution, increased on-board signal-processing capability to improve
clutter rejection, and enhanced reliability and survivability improvements.
In the 21st century, the Space-Based Infrared System (SBIRS) will replace
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 early warning capability. The original DSP weighed
2,000 pounds and had 400 watts of power, 2,000 detectors and a design
life of 1.25 years. In the 1970s, the satellite was upgraded to meet
new mission requirements. As a result, the weight grew to 5,250 pounds,
the power to 1,275 watts, the number of detectors increased by threefold
to 6,000 and the design life was three years with a goal of five years.
The 21st Space Wing, located 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
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 50th Space Wing at Schriever AFB, Colo., provides
command and control support for the satellites.
The Defense Support Program is managed by Space and Missile
Systems Center (Air Force Materiel Command), Space Based Infrared System
Program office at Los Angeles AFB, Calif. The office 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).
DSP's 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.
Primary mission: Strategic and tactical missile launch
Contractor team: Thompson Ramo Woolridge (TRW) and Aerojet
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
Point of Contact
Air Force Space Command, Public Affairs Office
150 Vandenburg Street, Suite 1105
Peterson AFB, Colorado 80914.
692-3731 or (719) 554-3731.