The Defense Support Program (DSP) is a program of the

United States Space Force The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's only independent space force. Along with its sister branch, the U.S. Air Force, the Space ...

that operated the

reconnaissance satellite A reconnaissance satellite or intelligence satellite (commonly, although unofficially, referred to as a spy satellite) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. The ...

s which form the principal component of the ''Satellite Early Warning System'' used by the United States. DSP satellites, which are operated by the 460th Space Wing, detect

missile In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket i ...

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

launches and

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...

explosions using sensors that detect the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

emissions from these intense sources of heat. During

Desert Storm The Gulf War was a 1990–1991 armed campaign waged by a 35-country military coalition in response to the Iraqi invasion of Kuwait. Spearheaded by the United States, the coalition's efforts against Iraq were carried out in two key phases: ...

, for example, DSP was able to detect the launches of Iraqi

Scud A Scud missile is one of a series of tactical ballistic missiles developed by the Soviet Union during the Cold War. It was exported widely to both Second World, Second and Third World, Third World countries. The term comes from the NATO reporti ...

missiles and provide timely warnings to civilians and military forces in Israel and

Saudi Arabia Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in Western Asia. It covers the bulk of the Arabian Peninsula, and has a land area of about , making it the fifth-largest country in Asia, the second-largest in the A ...

. The satellites are in

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

s, and are equipped with infrared sensors operating through a wide-angle

Schmidt camera A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt in 1930. Some notable exa ...

. 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 IV Titan IV was a family of heavy-lift space launch vehicles developed by Martin Marietta and operated by the United States Air Force from 1989 to 2005. Launches were conducted from Cape Canaveral Air Force Station, Florida and Vandenberg Air Forc ...

B boosters with

Inertial Upper Stage The Inertial Upper Stage (IUS), originally designated the Interim Upper Stage, was a two-stage, solid-fueled space launch system developed by Boeing for the United States Air Force beginning in 1976 for raising payloads from low Earth orbit to h ...

s. However, one DSP satellite (DSP-16) was launched using the

Space Shuttle Atlantis Space Shuttle ''Atlantis'' (Orbiter Vehicle designation: OV‑104) is a Space Shuttle orbiter vehicle which belongs to NASA, the spaceflight and space exploration agency of the United States. ''Atlantis'' was manufactured by the Rockwell Inte ...

on mission

STS-44 STS-44 was a NASA Space Shuttle mission using '' Atlantis'' that launched on November 24, 1991. It was a U.S. Department of Defense (DoD) space mission. Crew Backup crew Crew seating arrangements Mission highlights The launch wa ...

(24 November 1991). The last known DSP satellite (flight 23) was launched in 2007 aboard the first operational flight of the

Delta IV Heavy The Delta IV Heavy (Delta 9250H) is an Evolved Expendable Launch Vehicle, expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It is the world's third highest-capacity launch vehicle in operation, behind NASA's Space L ...

rocket, as the Titan IV had been retired in 2005. All 23 satellites were built by the prime contractor

Northrop Grumman Aerospace Systems Northrop Grumman Corporation is an American multinational aerospace and defense technology company. With 90,000 employees and an annual revenue in excess of $30 billion, it is one of the world's largest weapons manufacturers and military techno ...

, formerly TRW, in Redondo Beach,

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. The 460th Space Wing, with headquarters at

Buckley Space Force Base Buckley Space Force Base is a United States Space Force base in Aurora, Colorado named after United States Army Air Service First Lieutenant John Harold Buckley. The base is run by Space Base Delta 2, with major units including the U.S. Space For ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

, has units, primarily the 2nd Space Warning Squadron, that operate DSP satellites and report warning information, via communications links, to the

NORAD North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection ...

and

USSTRATCOM United States Strategic Command (USSTRATCOM) is one of the eleven unified combatant commands in the United States Department of Defense. Headquartered at Offutt Air Force Base, Nebraska, USSTRATCOM is responsible for strategic nuclear deterr ...

early warning centers within the

Cheyenne Mountain Space Force Station Cheyenne Mountain Space Force Station (CMSFS) is located in Cheyenne Mountain on the Front Range of the Rocky Mountains in unincorporated El Paso County, Colorado, next to Colorado Springs, The Cheyenne Mountain Complex, an underground facili ...

, Colorado. These centers immediately forward data to various agencies and areas of operations around the world. The SBIRS Wing at the

Space Systems Command Space Systems Command (SSC) is the United States Space Force's space development, acquisition, launch, and logistics field command. It is headquartered at Los Angeles Air Force Base, California and manages the United States' space launch ...

Los Angeles Space Force Base LOS, or Los, or LoS may refer to: Science and technology * Length of stay, the duration of a single episode of hospitalisation * Level of service, a measure used by traffic engineers * Level of significance, a measure of statistical significan ...

, California is responsible for development and acquisition of the satellites.

History

The Defense Support Program replaced the 1960s space-based infrared

Missile Defense Alarm System The Missile Defense Alarm System, or MIDAS, was a United States Air Force Air Defense Command system of 12 early-warning satellites that provided limited notice of Soviet intercontinental ballistic missile launches between 1960 and 1966. Original ...

(MIDAS). The first successful launch of

MIDAS Midas (; grc-gre, Μίδας) was the name of a king in Phrygia with whom several myths became associated, as well as two later members of the Phrygian royal house. The most famous King Midas is popularly remembered in Greek mythology for his ...

(MIDAS-2) was 24 May 1960 and there were twelve launches before the DSP program replaced it in 1970. The first launch of a DSP (IMEWS-1 - Integrated Missile Early Warning Satellite) was on 6 November 1970 and since then it has become the mainstay of the United States ballistic missile early warning system. For the last 45 years they have provided an uninterrupted space-based early warning capability. The original DSP satellite weighed 2,000 pounds (900 kg) and had 400 watts of power, 2000 detectors and a design life of 1.25 years. Throughout the life of the program, the satellite design has undergone numerous improvements to enhance reliability and capability. The weight grew to 5,250 pounds (2380 kg), the power to 1275 watts, the number of detectors increased threefold to 6000 and the design life has been increased to a goal of ten years. STS-44 DSP deployment

The 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 and improved resolution. Increased on-board signal-processing capability improves clutter rejection. Enhanced reliability and survivability improvements were also incorporated. The 23rd, and last DSP satellite (DSP-23) was scheduled to be launched on 1 April 2007, aboard a Delta IV Heavy rocket, but the launch was postponed until mid-August 2007 after two structural cracks were found in the metal launch table at pad 37B, caused by a fuel leak during testing. Further delays forced the launch back to 11 November 2007, when the satellite launched at 01:50:00 UTC (20:50 EST on 10 November). This satellite died in space sometime during 2008, for reasons unknown. It is now adrift in geosynchronous orbit and remains a potential hazard to other craft. The Department of Defense sent a

MiTEx The Micro-satellite Technology Experiment (MiTEx) is a microsatellite-based mission launched into geosynchronous orbit 21 June 2006 aboard a Delta II rocket. The USAF described the mission as a "technology demonstration" for the Defense ...

spacecraft to inspect DSP 23 sometime in 2008. Another DSP satellite was lost in 1999, DSP-19, after its

failed following launch from a Titan 4B booster. DSP-19 was a USAF Defense Support Program missile early warning satellite equipped with an

infrared telescope An infrared telescope is a telescope that uses infrared light to detect celestial bodies. Infrared light is one of several types of radiation present in the electromagnetic spectrum. All celestial objects with a temperature above absolute zero ...

to detect rocket launches. The Titan 4B rocket placed the IUS upper stages and payload into a 188 km x 718 km x 28.6° parking orbit. The first stage on the IUS burned at 18:14 GMT and put the second stage and payload into a geosynchronous transfer orbit. The IUS second stage fired at 23:34 GMT. However, the two stages of the IUS failed to separate completely. At least one connector remained attached. This meant the second stage motor nozzle did not extend properly. When the stage fired, the vehicle tumbled during the burn and the satellite was left out of control in a useless orbit. The project was originally to have had 25 satellites, but the last two have been canceled, mainly due to SBIRS. DSP satellites have been replaced by the

Space-Based Infrared System The Space-Based Infrared System (SBIRS) is a United States Space Force system intended to meet the United States' Department of Defense infrared space surveillance needs through the first two to three decades of the 21st century. The SBIRS prog ...

(SBIRS) satellites. There were five major improvement programs on the 23 satellites: * Block 1: Phase I, 1970–1975, five satellites * Block 2: Phase II, 1976–1987, seven satellites * Block 3: Multi-Orbit Satellite Performance Improvement Modification (MOS/PIM), 1989–1991, three satellites * Block 4: Phase II Upgrade, 1994–1997, two satellites * Block 5: DSP-I (DSP-Improved), 1999–2007, six satellites More recently, there has been some effort put into using DSPs' infrared sensors as part of an early warning system for natural disasters like volcanic eruptions and forest fires.

Limitations

The DSP constellation may have offered an excellent vantage point for an early warning system against state-centric threats such as missiles, but military analysts warn its ability to collect intelligence on non-state actors is severely limited.

General characteristics

* Primary mission: strategic and tactical missile launch detection * Contractor team:

, formerly TRW (for satellite bus) and

Northrop Grumman Electronic Systems Northrop Grumman Electronic Systems (NGES) was a business segment of Northrop Grumman from 1996 to 2015 until a reorganization on January 1, 2016 merged other Northrop Grumman businesses into NGES to form a new segment called Mission Systems. NG ...

, formerly Aerojet Electronics Systems (for IR sensor) * Weight: 5,250 lb (2,380 kg) * Orbit altitude: 22,000 miles (35,900 km) * Power plant: solar arrays generate 1485 watts * Height: 32.8 ft (10 m) on orbit; 28 ft (8.5 m) at launch * Diameter: 22 ft (6.7 m) on orbit; 13.7 ft (4.2 m) at launch * Date first deployed: 1970 * Date late deployed: 2007 * Latest Satellite Block: satellites 18–23 * Unit Cost: US$400 million

Gallery

Image:2d Space Warning Squadron.png, 2d Space Warning Squadron Image:8th Space Warning Squadron.png, 8th Space Warning Squadron Image:11th Space Warning Squadron.PNG, 11th Space Warning Squadron Image:DSP Flight 1.png, DSP Flight 1 Image:DSP Flight 2.png, DSP Flight 2 Image:DSP Flight 3.png, DSP Flight 3 Image:DSP Flight 4.png, DSP Flight 4 Image:DSP Flight 5.png, DSP Flight 5 Image:DSP Flight 7.png, DSP Flight 7 Image:DSP Flight 8.png, DSP Flight 8 Image:DSP Flight 9.png, DSP Flight 9 Image:DSP Flight 10.png, DSP Flight 10 Image:DSP Flight 13.png, DSP Flight 13 Image:DSP Flight 14.png, DSP Flight 14 Image:DSP Flight 15.png, DSP Flight 15 Image:DSP Flight 16.png, DSP Flight 16 Image:DSP Flight 17.png, DSP Flight 17 Image:DSP Flight 18.png, DSP Flight 18 Image:DSP Flight 1 Launch 6 Nov 1970.png, DSP F1 Launch 6 November 1970

References

External links