Defense Support Program

The Defense Support Program (DSP) is a program of the U.S. Air Force that operates the reconnaissance satellites which form the principal component of the Satellite Early Warning System currently used by the United States.

DSP satellites, which are operated by the Air Force Space Command, detect missile or spacecraft launches and nuclear explosions using sensors that detect the infrared emissions from these intense sources of heat. During Desert Storm, for example, DSP was able to detect the launches of Iraqi Scud missiles and provide timely warnings to civilians and military forces in Israel and Saudi Arabia.

The satellites are in geosynchronous orbits, and are equipped with infrared sensors operating through a wide-angle Schmidt camera. The entire satellite spins so that the linear sensor array in the focal plane scans over the earth six times every minute.

Typically, DSP satellites were launched on Titan IVB boosters with Inertial Upper Stages. However, at least one DSP satellite was launched using the Space Shuttle, the known example being Atlantis on mission STS-44 (November 24, 1991).

The last known DSP satellite (flight 23) was launched in 2007 aboard the first operational flight of the Delta IV Heavy rocket, as the Titan IV had been retired in 2005. All 23 satellites were built by prime contractor Northrop Grumman Aerospace Systems, formerly TRW, in Redondo Beach, CA.

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