Defense Support Program (DSP) Satellites

Mission

The Defense Support Program (DSP) satellites provide early warning for Intercontinental Ballistic Missile (ICBM) and tactical launches. This once classified satellite was first launched in 1970 and became the first of 23 to be launched over the next 37 years. DSP satellites use infrared sensors to detect heat from missile and booster plumes against the Earth's background in support of the missile early warning and missile defense mission areas.

Description

The legacy DSP constellation is operated from the Space Based Infrared System (SBIRS) Mission Control Station (MCS) at Buckley Air Force Base, CO. DSP is managed by the Remote Sensing Systems Directorate (RS) at the U.S. Air Force Space and Missile Systems Center.  Contractors for the DSP satellite were TRW (now Northrop Grumman Aerospace Systems) for the spacecraft and Aerojet (now Northrop Grumman Electronic Systems) for the infrared sensor. 

DSP grew out of the successful 1960s space-based infrared Missile Defense Alarm System known as MIDAS. The first successful launch of MIDAS was 24 May 1960. Between 1960 and 1966, 12 MIDAS launches deployed four different types of increasingly sophisticated sensors, leading the way to the development, launch, and use of DSP.

On 6 November 1970, the U.S. Air Force launched the first DSP satellite on a Titan IIIC rocket from Launch Complex 40 at Cape Canaveral Air Force Station, Fla.  DSP had a history of launching atop Titan III and IV family of launch vehicles (to include the Titan addition of the Solid Rocket Motor Upgrade) with two exceptions. DSP-16 was launched aboard NASA's Space Shuttle Atlantis in November 1991.  The final launch, DSP-23, was carried into geosynchronous orbit by United Launch Alliance’s Delta IV Heavy launch vehicle in November 2007, the first operational launch for that launch vehicle.

Since the early 1970s, DSP has been the backbone of the ballistic missile early warning system of the United States.  The primary mission was to provide early warning to command authorities of intercontinental ballistic missile (ICBM) launches from anywhere in the world that could impact North America.  As the program evolved, the mission was expanded to also provide early warning for shorter-range theater ballistic missile launches to support theater commanders in relevant areas around the world.  Initially, DSP ground stations were distributed all over the globe, with each station receiving data from the satellites in their field of view.  The SBIRS MCS achieved Initial Operational Capability (IOC) in December 2001, which consolidated ground operations of all DSP satellites in a single location.  The DSP mission also includes providing detection of nuclear detonations high above the earth via a secondary sensor.  DSP data is transmitted to the MCS where the data is processed and messages are released in near real-time onto appropriate communication networks for each of these missions.  In addition, data processing has also been developed and implemented at the MCS ground site to extract special events, which are also sent out as messages to commanders. 

In recent years, scientists have developed methods to use DSP's infrared sensor as part of an early warning system for natural disasters like volcanic eruptions and forest fires. In addition, researchers at The Aerospace Corporation have used DSP data to develop portions of a hazard support system that will aid public safety in the future.

System Features

In response to the evolving threats, DSP has undergone five major upgrades that allowed it to provide more accurate and reliable data to the warfighter. For example, the addition of a medium wavelength infrared capability has provided enhanced missile warning mission utility. This upgrade marked the first space sensor application of mercury cadmium telluride infrared sensors, the material of choice for today's infrared sensors. All of the DSP satellites were spinning satellites with the infrared sensor at the front end of the spacecraft.  The DSP satellites orbit the earth approximately 22,000 miles over the equator. The current DSP spacecraft is more survivable than its predecessors, accommodates 6,000 detectors, uses approximately 1,275 watts of power, with an on-orbit weight of approximately 5,200 pounds at the beginning of life, including fuel.   

• Block 1: Phase I, 1970-1973, 4 satellites

• Block 2: Phase II, 1975-1977, 3 satellites

• Block 3: Multi-Orbit Satellite Performance Improvement Modification (MOS/PIM), 1979-1984, 4 satellites

• Block 4: Phase II Upgrade, 1984-1987, 2 satellites

• Block 5: DSP-1, 1989 - 2007, 10 satellites launched

• First launch on 6 November 1970

• Final launch on 10 November 2007